Hey everyone!

Car is a 1971 Olds Cutlass S. Now that my rearend is done (1971 10 bolt 8.5 with 3.23 gears an eaton truetrac),
I am thinking more and more about to beef up/rebuild my 71 350.

The engine runs very well and ive already did a 4bbl swap with the olds performer 350 intake from edelbrock and the right Q-Jet for year 71. Ive already use an MSD ready to run distributor with blaster 2 coil. Valvetrain, pistons, cam and so on is still stock. Heads are #7, which i think are the right for 71.

My goal would be a streetable olds 350 which make a good bang off the line. I do not race the car (here in Austria we dont have drag strips ).

So, i bet that this has beed discussed many times before, but i just wanted to have answers/ideas to my specific build.

Here are a few questions:

-Can i reuse ma #7 heads? I was thinking about 9.5 to 1 compression ratio.

-Which Pistons would you recommend for that? I would like to re-use my stock crank and connection rods. Is this a good idea?

-what would be a good choice for the cam kit? I read that the lift is limited when use stock heads. I dont care about 'how it sounds', i just want the best specs for my setup.

-what to do with the #7 heads? Is it a good idea to re-use them? Maybe with a 3 angle valve job?

-do i need a high-volume oil pump for a setup like this?

Thank you all for every idea and help

Greetings from Austria

 

Contact Cutlassefi, Mark Remmel his email is Fastone01@hotmail.com, brought Mahle 10cc dish forged pistons with modern 1mm ring packs to the market. They will give you the 9.5 to 1 you want. You have huge 24cc factory dish pistons, either new pistons or a ton of head milling which cause intake fitment issues. There is even a 4.065" Mahle oversized piston that allow just a hone to fit, if the block is in good shape. You would have to explain this to the machinist that this size piston exist. Also new cam bearings, balancing the engine and a crank grind may be needed. Ask his advice for a cam, probably something in the 220 duration range. Lift has to do with stock rockers being limited to around .500" lift. He has a few cams that work with the stock lifters. Get the matching springs for the cam, 2"/1.625" W31 valves and get the bowls opened with a cutter and a multi angle valve job. Also any worn guides replaced and something like positive seals can be added. Lastly, your Qjet may need idle circuit and possibly richer jetting and rods to run right. Good luck.

 

If the engine runs fine, I'd say keep running it. Mark will probably suggest the TQ40...ha. But really...valve springs, timing chain, cam, maybe roller rockers. No need to spend money replacing an engine that's doing fine.

 

The stock cam is very mild but he also has 8 to 1 compression, he needs to stay mild. The largest he should go is the 204/214 cam with the motor as is. A new timing set and dual exhaust should be added if not done already. A 2000+ converter will help launch, stock is a very lame 1600 rpm.

 

Yes i knlw about the low compression, thats why im thinking about changing pistons. Dual exhaust is already done. Im thinking about a 2400 converter ..

 

Have you driven it with the current mods ? If so I am guessing the mods have not made enough of a difference for you ? Or are you just on a roll modification wise and figure keep it going till you hit a stop ?

Seeing that you have a great running engine, and are not really interested in 1/4 mile, I say tweak as you have been doing with bolt ons without opening up the engine. Olds 307 and 403 knows his stuff but I am leaning with Brownbomber on this one. Would do everything but mess with the original engine unless you want an all out beast.

I understand you are not a 1/4 mile guy, but very hard to reference performance with butt dyno only. So bear with me. Factory your car dual exhaust and 4 bbl was likely a 17 second car in the 1/4 mile. If you get and ideal go package, great rear gear, a better converter as Olds 307 and 403 suggested, maybe a shift kit on the TH350 you could see mid 15s. That will feel plenty powerful on the street but if you want to tangle with modern 400 HP grocery getters, an all out build is likely a must.

P.S. 200 net HP can run a 15.5 @ 88 MPH on a perfect pass with a great setup, that's as good as it gets with a 3800 LB car.

 

yes, i drive with the mods ive done since about 2 years. I made them step by step. First, i swapped from the original 2bbl with iron intake to the right 1971 qjet with edelbrock performer intake and hooker long tube headers and MSD ready to run.

Next step was to put the transgo 1-2 shift kit in my th350 and 2 weeks ago, i changed my 2.56 open rear to 3.23 with an eaton truetrac carrier.

maybe i have to try out a converter with higher stall speed, even if i let my engine be like it is at the moment. I still drive the stock one with about 1500? Stall.

All these mods made it a totally different car. It runs a lot better than stock.

what bothers me, is that with the stock compression ratio, it woudnt make much sense to do a cam swap. Even i think its very annoying that at about 5000 rpm the engine is at its limit and the valves are floating .

Thanks to all for your help!

 

Way back in the 1980s I had to rebuild the engine in my car (350-4bbl) but I retained the factory camshaft. The engine wouldn't pull past 5000 RPM, then I installed a .435" lift, 204º duration camshaft and it was a huge improvement, and with new valve springs the engine would pull well past 5000 RPM.

The factory cam is puny, with .400" lift and 186º @ .050", so a cam with .450-ish lift and around 204º duration (RV cam profile) would be a noticeable improvement.

 

Ok, so i see, most of you woudnt change pistons ect..?

ok, i bet rebuilding an engine in the car isnt that much fun

Thank you, so which brand for a cam would you recommend? So is this "valve floating" really just a problem of weak valve springs? I mean, for sure that with the stock cam there wouldnt be much more power on 5000 rpm, but hell, i doesnt want my valves to float around. I sounds/and feels terrible. And like i wrote in my other thread, i cant even do a kickdown without having the fear my valvetrains going to explode

I was just thinking of maybe rebuild the engine completely, even because i love the mechanical work and a nice running engine which makes a good bang would be the top of the cake for my cutlass project

The problem is, here in Europe, we havnt that much choice in parts for olds engines (no problems if you have a chevy 350 ), and we dont have a lot of machine shops for engines. And when there is one its very expensive. Even parts gathering is much more difficult because i have to order all from the US and shippings very expensive too

Which setups are you guys running on your 350?

Does someone has a similar 350 like mine?

Greetings from Austria

 

Well, i live in Finland. I have probably more money at shipping costs and taxes than actual parts... But thats life i quess, noone forces to this hobby. And agree, for Chevrolet even here at Europe, theres parts to get for cheap. And Mopar. And actually Ford too. All the others are weird and forgotten here almost.

If youre not racing it, id check just the condition of internals etc, and if nothing needs rebuilding... Id leave it as it is. Rebuild the heads, maybe light porting, and call it a day. Anything else does burn alot of money. Alot. Theres also the good old SpeedPro pistons too, no need to go Mahles for that build. Everything new aint "must have", but its the jive of nowadays. Plus you can get a cam without cutlassefi, hes not grinding his cams either, he uses others to do that.

Your gear ratio is spot-on for European speed-limits, really works with them and 3-speed trans. If you do calculations, something around 2000 stall speed ( verified) would be pretty optimal. At 80km/h, those gears and some wheels, youll be cruising at around 2000rpm there. Get more and you would be under the stall, and when arriving steep degree ( like in Austria) youd be first heating trans fluid..

 

I have the **** pistons as well, Mark did this cam for me 208/214@.050with .460/.476 lift, that cam feels and sounds so good. I went with the Hughes 2500 stall with 3.08 gears and I really like it Do I want more, yes, but I have a fun driver while a build a motor up slowly. So I would say get a stall if you want a little more off the line

 

There is no reason these days to ever run Speed Pro pistons in a SBO. The Mahles are light years ahead. And if you have some petty vendetta against Mark or Mahle, you can run SBC pistons that are also light years ahead of those ridiculous Speed Pros.

Most machine shops/builders don’t grind their own cams. Vortecpro doesn’t, Travato doesn’t, Rocket Racing doesn’t. Those shops don’t manufacture their own blanks either! They don’t forge or machine their own pistons! Or rods! They use off the shelf bearings even!!!

The builder comes up with the profile and sends it out to be ground. No different than the original engineer who designed the original engine. He didn’t grind the cam either.

If you’re going to trash the guy who is almost universally recommended on this forum despite his excellent reputation, you’d better be bringing some heavy recommendations for someone else. So spit it out. Who has ground you a custom Olds cam?

 

Speedpro pistons are heavy, old school ring packs and often put in without enough clearance thanks to the box and also the instructions giving the wrong clearances. Overheating and good times happen. I agree, Cutlassefi has been good to deal with, thrown in free stuff and matched the big store prices. He offered me $100, 100 mile used roller lifters and got me the awesome Accel 25 ohm race wires being discontinued for the Clearance price that Holley would not ship to Canada. It makes getting a roller cam much easier for me. Either way, do a compression test, put an oil gauge on it and figure out your budget. Good luck.

 

It has nothing to do with Vendetta, it has to do with the fact that people forgot there are other ways to do it aswell, which the lap dogs so easily forgot to mention. Give em candy and theyr all yours without questioning anything, ever. Thats disgusting to look at.

If we go that way, the SBO itself is ancient design aswell, these are pieces of crap compared to what we have available nowadays. So are the cars. So- its not about the latest high-tech, its about the passion and love to old cars. And when speaking about old cars, you dont need the latest and best gizmo/ gadget. I wonder how the Oldsmobile world did for 40 years without Mahle-pistons. I quess no records are set with Mahles either.

That Austrian guy would again do good enough with Speed Pros, even some generic cam off-the-shelf.

 

Isn't there an aftermarket piston set, which is the same, or near the same as the stock "without dish" pistons? Like in the pre 1971-olds 350 engines?

I don't think that i have to go too exotic.

even, if most of you say that it makes not much sense to rebuild the engine with new pistons, which cam-lifters-valve springs kit would you recommend?

 

Again, he has a stellar reputation on this forum. He has the experience of building all manner of Olds engines and has seen what works and what doesn’t and with experience comes recommendations FAR better than any first timer picking a generic grind out of a catalog. So again, put up or shut up. Recommend someone else who has the experience to provide an excellent cam grind for an Olds. Even better if you can find someone who offers that advice for free with no expectation of a sale...

As for pistons, there, again, is absolutely no reason to go with speed pros. Better options exist. We aren’t talking about massive price differences that would normally sway the decision. By the time you factor in everything that goes with replacing pistons, the cost difference is negligible. You get better performance and better longevity out of a better piston. There are no downsides at all. You’re arguing for junk pistons because you absolutely do have a very petty vendetta against him. It shows. You can deny all you like, but you’re as transparent as glass.

OP, if you’re replacing pistons, get good ones. If you don’t need to replace pistons, don’t. If you need a cam, talk to mark (Cutlassefi). He’s helped a ton of people on this forum (myself included) and is the go to guy for this sort of thing, despite the pettiness from guys like Inline.

 

The reason to go with speed pros is because you can usually pick up lightly used sets for cheap. I have a few and although out of date and heavier than a contemporary piston. They work. I put together an entire combination for a guy with a 8.5 to 1 ( aftermarket dished Pistons .045 in block) short block 7 heads , a 260 h cam from comp , edlebrock RPM intake. I built the trans added a 2200 stall and a 3.42 and he loves it. Plenty of pep. It will shred tires and it was inexpensive. His first time out with no racing experience he clicked off a 14 sec pass with a full dressed. Car. Just for what it's worth. Imo if a car car shred the tires and have enough power to pass cars . That's enough for a cruiser.

 

This sounds very interesting. Have you let the #7heads stock? New valve springs?

Im going to take a look if theres a kit for the Comp 260 H cam which includes lifters and valve springs.

Since, i already have 3.23 gears, headers, Qjet and edelbrock performer (3711) intake, it looks like im going to gather a cam kit, new timing chain and a 2200 stall converter. Any recommendations for converter brand?

one more question, is it necessary to add an extra trans fluid cooler when using a converter like this? Or is the stock radiator cooling good to go with 2200 stall?

maybe this is better than to do a full engine rebuilt on a street/nice weather fun car.

Thanks a lot for the help!

 

That Comp cam looks pretty decent and being ground on a 110 LSA will help. Yes, get the matching springs but don't 71 have different depth spring pockets? Also put new valve seals while in there. Comp came double roller timing set should be avoided, very inaccurate. The Cloyes billet set, which is expensive or their basic replacement timing set or the Summit brand if looking to save a few bucks. Also the Summit 2000 to 2300 stall is very affordable and well rated for the TH350.

 

I have a Hughes Performance converter and I really like it. Be sure to get the one with threaded lugs for Buick/Pontiac/Olds applications.

https://www.summitracing.com/parts/hup-gm20bpo

https://www.summitracing.com/parts/hup-gm25-bpo

I have not needed an external trans cooler, even in the Phoenix summer heat. It all depends upon how much slippage the converter has, and I measured the Hughes to be around 250-300 RPM at highway speeds, so same as a factory converter.

 

Good point 71, my understanding is the Summit converter is the lug style and made by B+M. The chebby style bolt and nut converter hits balancing weights on the flex plate in some cases.

 

For some reason both fun71 links produce the same convertor, A little more money but I run the HD version.

https://www.summitracing.com/parts/h...pohd?rrec=true

 

I have had good results with the jegs converters

 

Sorry, my bad, the 2000 to 2300 Jegs converter is the one you probably want, made by B+M. The Summit one has mixed reviews. Brain fart.

 

I grabbed the link to the GM25-BPO from a sidebar on the GM20-BPO page, and it appears the link was still directing to the GM20-BPO page. I corrected the link in my post above.

https://www.summitracing.com/parts/hup-gm25-bpo

 

So, i think the Hughes GM20 BPO is the way to go, thank you all for the help!

whats the difference between GM20 HD and non HD?

 

Speaking of lap dog....Get your head out of Vortec Pro's ***. You make insulting comments towards a lot of us, check your attitude at the door. We told him other ways to get parts through the major parts places. An 8 to 1 350 is easy to overcam and 50 years old, he might have 50 psi through the cylinders and low oil pressure. A compression and oil pressure test tells him what his motor will need. These are great motors but it may have been abused and neglected for 50 years. Are you telling me modern pistons aren't worth $100, then sure, go for it. Why not do some improvements to improve our ancient design? Modern engines make more power because of many things, low drag pistons with super thin rings are one of them. If he uses Speedpro pistons, the machinist better be told about the .004" minimum clearance, not the .001 the box says or .002" the instructions say. He will need the 6cc dish, not the easier to find flat top version, over 10 to 1 with that. Not easy to get some parts here either, Cutlassefi has helped me get parts that the big places would not ship over the border. Summit won't ship an early Turkey tray or spark plugs over the border to Canada. Instruments of terrorism I believe was the answer from Summit. Like I said, do a compression test and put an oil gauge on the motor before any decision is made. And the "Candy" he has brought to the market has helped a motor, my favorite the Olds 350 be more than possible before. When was over 400 ci possible from an Olds 350 gas motor, never without big, big dollars.

 

So, the comp 260h CL42-228-4

would be a good choice for stock compression and stock heads (#7)?

This kit comes with lifters as well.

Would you recommend to pull the heads while swapping the cam and replace the head gaskets, clean/give the valves a new grind-in, replace valve seals and valve springs?

 

not looking to feed the Speedpro s***storm but I have their .030 over flat tops in my '72 SBO and my CR is right around 9.5 - I run 90-93 octane all day long without issue. Built my engine using a 2711 E-brock intake, a Qjet level 2 performance build from Ken at Everyday performance, the original 7a heads completely gone thru and milled .003 (block deck milled .007 as well), Cloyes billet double roller timing chain, Comp stock rockers set, MSD 8529 electronic distributor and I'm using the Howards CL510011-12 cam/lifters kit.
Duration Exhaust: 269
Duration Intake: 259
Duration at 050 Exhaust: 215
Duration at 050 Intake: 205
Intake Centerline: 108
Lobe Separation: 112

In retrospect, I didn't know about the Mahles when I built the motor (now going on approx. 4 years ago) or I probably would have gone that route but I'm otherwise not the least bit unhappy with how my motor turned out with the Speedpro set.

I had the Hughes HD2500 converter but it took an early dump for unexplained reasons so I'm currently running a 23 -2600 stall converter. Rear gears are 3.08 posi
I do have a 455 with '70 big valve E heads sitting in my garage for a future build once I can get with Mark to lay it out but for now my SBO is a fun motor.

 

You can, the valves could no doubt benefit from a multi angle valve job. Also guide wear should be checked and a bowl hog cut under valves help flow. Unless about .020" is removed from the head, you will lose compression. The factory steel shim gaskets are .017" thick and Felpro and many others are .038" to .041" thick. You can CC your heads and measure how far the factory 24cc pistons are below deck to get your exact compression ratio.

 

Ken going through my Qjet helped my motor as well, lessened pinging a lot, much closer to the proper tune, I gave him my specs. What was your head CC? How far below deck did the pistons end up? The Speedpro are a strong piston, just very heavy with thick rings. They are better than the weak and heavy, with huge dish cast replacement pistons. I had pinging issues on 91 with the same cam, actually an Edelbrock on a 114 LSA, two degrees advanced. I had 55cc heads on a stock 76 short block. So 14cc pistons .025 to .030" in the hole with .041" Felpro head gaskets, not ideal. I needed cold plugs and conservative timing. Less fun on the street but 14's at the track.

 

The Mahle pistons weren’t available 4 years ago.

 

Which valve springs would you recommend to use with the comp 260H cam?

 

Stock springs where fine with mine when I did my engine

 

Yeah, I have ran stock springs with the 204/214 cam multiple times. Keep it under 5000 rpm and it should be fine.

 

I guess Stock replacement? Or keep the original springs?

I want to get new Valve springs, i bet mine are as old as the engine is sn have never been replaced.

could i use the comp cams 901-16 set?

 

Yeah, thats the point. At 5000 or a bit more rpm, i have a terrible valve floating.

I thought this could get a bit better with new springs.

 

Have your stock springs checked . If they are good re use them but if not replace with a suitable set. Stock or entry level aftermarket are priced about the same. I paid 120 for a high performance double spring set

 

Back in 1982 when I first rebuilt my engine the original springs were shimmed during the valve job (engine had 99,000 miles at the time). I discovered the valves would float at 5000 RPM, so I installed new springs (single spring with damper) and the engine would pull to 5800 RPM with no issues. So yeah, new springs for sure.

 

Quote:

Originally Posted by 71OldscutlassS

yes, i drive with the mods ive done since about 2 years. I made them step by step. First, i swapped from the original 2bbl with iron intake to the right 1971 qjet with edelbrock performer intake and hooker long tube headers and MSD ready to run.

Perfect, and at the same time you have just about maxed your car out with the basic bolt-ons...



Very nice, I would of went with 3.42 but done is done. I have the same shift kit sealed in its box for years now. Maybe one day it will make its way into the transmission.



This should be a game changer, talking to guys at the track over the years and trying to figure out why my car was not quicker as is. Resulted in the stock converter being considered the biggest culprit followed by the rear gear.

Track reference; 60 ft time, the time it takes to cover the first 60 feet of a race. Quick cars cover that distance in about 2.0 seconds or less when ideally setup with a certain power to weight ratio. Cars like ours take about 2.5 seconds. A more aggressive torque converter is key to improving this aspect of a cars performance. My best 60 ft time is 2.332 which is so bad vs my cars actual end result of a 15.5 @ 89.5 its remarkable. 2.332 works out to a 17 @ 79 MPH pass. Obviously improving my cars 60 ft will make my car considerably quicker. Same goes for your car. ( Rear gear plays a roll in this as well, but our engines have a decent amount of torque which compensates a bit for a terrible performance gear like my 2.78... Your 3.23 on the other hand is a nice gear, so you are already cooking with gas so to speak.)

My best MPH indicates my 60 ft should be 2.0 seconds and my car should run 14.7, as you can see our basic drive-trains are very inefficient.




Awesome, so you are happy and its going in the right direction. But you want more which is understandable.