1968CutlassSupreme

Hello everyone!

I am looking into buying some parts for the spring (already asked about headers). I had some correspondence about this but I've slept since then....

What do you all think are good (and attainable - the Q-Jet carb is hard to find thus far) intake / carb combos for the rocket 350. I am working to set the engine up for around 400 hp. I will be eventually machining the block and heads (balancing the engine, machining the heads for the W31 valves and porting them to match the intake [if I understand that correctly], a cam from Mark [cuttlasefi] and the valve train that goes with it, etc), but for now I am working on the "bolt-ons" and will take care of the insides when that time comes. I would like a combo that is just enough to perform well - I get the impression that some always think bigger is better, and I heard from someone once that the carburetor should be just enough (and not slapping a 850 double-pumper on a small block ).

Anyway, any suggestions would be great. BTW, I heard there was an Edelbrock manifold (something like a 2711 or 3711) that matched well with an Edelbrock 650cfm four barrel. Is that something good?

Thanks everyone. I appreciate your help and correspondence. It's a lot of fun around here.

cutlassefi

To achieve 400hp you'll need an Edelbrock 7111, a 750, some minor headwork, approx. 9.75-10.0:1 and the right cam.


Hope this helps.

captjim

I had an RPM intake and a 770 Holley Street Avenger (VERY easy to tune) and it ran great in a pretty hot 355. Just my opinion, but Oldsmobiles "like" big carbs.

Bernhard

We ran a holly street dominator with a Qjet ,headers, mild cam, and 411 gears.
Worked real good with w31 stock iron heads.
They don't make the street dominator anymore but they come up all the time in the classifieds on ROP, Classic Olds, high performance Oldsmobile , and Olds power.

olds 307 and 403

Everyone seems to love the Quickfuel Slayer series 750 cfm, a lot of carb for $300. The 750 Street Demon is also another great choice but mileage probably isn't a priority on a high performance motor. 600 cfm and a Performer will choke a high winding motor like you want. The RPM intake is much taller with bigger runners. Don't forget a 2500 stall and 3.23 and up gears to go with the motor.

1968CutlassSupreme

Olds 307 and 403:

"The RPM intake is much taller with bigger runners."

What are the implications of this?

"Don't forget a 2500 stall and 3.23 and up gears to go with the motor."

When I work to machine the engine and do a total rebuild (beyond bolt-ons) I will be working on the stall converter - along with some questions, I am sure. As far as the 3.23 gears go, it seems I have a carrier that is too small to do anything with. Do you know what rear ends will fit under this car (like if I could buy a certain year camaro rear and or grand national or any other rear end that would fit)?

cutlassefi:

"To achieve 400hp you'll need an Edelbrock 7111, a 750, some minor headwork, approx. 9.75-10.0:1 and the right cam."

I am going to aim to set the engine up for a 10:1 compression by changing to forged flat top pistons. As far as the heads go I have #5 heads (which appear to have 65cc chambers) and I plan on having them reseated for the W31 valve train with a roller rocker setup. I will be contacting you for a cam when that time comes so I can have the best compliment for the rest of the modifications. Will the Edelbrock 7111 fit under the hood? If it doesn't are there any Olds hoods that would look good on my 68 that will have the room to fit it? My last question (for now) is will the intake / carb combo be too much for the engine before the internals of the engine are done?

Thanks for the responses everyone! Keep them coming, if you want, of course.

Somewhat unrelated question: do any of you spend time in an Oldsmobile related chat room? I found one called "Rocket Talk" but no one ever seems to be there.

oldcutlass

As long as you don't have an OAI, your good. Most dual plane manifolds should fit under the hood with an sbo.

Fun71

A complete rearend from any '68-72 A-Body will fit under your '68 Cutlass:
Buick Skylark/Grand Sport
Pontiac Tempest/LeMans/GTO, Grand Prix
Chevrolet Chevelle, Malibu, El Camino, Monte Carlo

You could also buy a carrier for your O-Type, either a used one or a new one. The new ones are Ford 8.8 carriers that have been machined to fit into the O-Type housing and accept O-Type ring gears. One of our resident differential gurus could likely help with whatever way you want to go.

Yes, it will fit.

I don't really understand this question. Do you plan to drive the car while you are building the engine? Do you have a different engine that you are building?
????

1968CutlassSupreme

oldcutlass: "As long as you don't have an OAI" - what is an OAI?

Fun71: What I mean is I am going to start buying the bolt on stuff and put them on as I get them (intake/carb, headers, timing chain and gear set, water pump) and then when I have a good chunk of change (about $1500, i guess) for machine work and new valve train I am going to disassemble the whole thing (with help) and have the machine work done and put it all back together. At least that is the plan for now - unless you all see what I am saying and tell me that it's an idiotic approach - then I'll have to reconsider based upon what is said.

Thanks!

olds 307 and 403

Basically the taller runners allow the engine to breath at higher rpm's. The runners are also taller on top, allowing the use of BBO heads with the 7111 intake.

oldcutlass

An OAI is the hood with the scoops.


Your plan is about the same as most I'd save about $3000. Things to consider are does the engine use oil or exhibit signs of blowby now? If yes, then save your money and do all of it at once.


After pulling the intake, remove all the rockers and stands (don't mix them up, they need to go back in the same postions), move the push rods and pop all the lifters (don't mix these up either) and inspect them to see if they are worn and concave on the bottoms. I'd also take a look at all the cam lobes for wear. If the lifters and cam are worn, then you have to decide on how to approach that issue.

jag1886

If you really are shooting for 400 HP you are definitely going to at least a RPM manifold and a 750 of some sort (I always lean towards a Holley).
I here people banter around that 400HP # and it takes a crap load of money to make that much HP from an Olds SB reliably. You need to put together a complete plan or you are going to spend a lot of money on things you will have to change down the road and that includes a pretty bullet proof drive train.

67 Cutlass Freak

This is very good information. No offense but I don't think you have planned this out too well. I would not purchase the upper end parts until you know exactly which components will work as a complete package for your entire build. I posted this in the Home Porting thread, but I think it applies here:


If you have just started planning your performance Olds build there's some very important things to consider. First and foremost what are your goals and how will your car be used. If it's strictly a drag race car, how fast do you want to go? A better question might be - how deep are your pockets? From the beginning we have been stressing the importance of having properly matched engine components. The only way to do this is to have all of the information about your combination ready to present to your engine builder, so he can steer you in the right direction. For example he will need to know the weight of your car, what transmission you are running, what differential gear ratio do you have, what tire wheel size, what type of fuel system are you running, and what modifications have been done to the chassis. Once you know all this then your builder will want to know what type of fuel you want to run. Now he can help you figure out what the optimum compression will be. Now you can choose the right head for your needs. Now that you know all that we can get a flow number and choose the right cam and valve train as well as intake and carb set up. I didn't type all this just for fun, but I think a lot of guys just start picking up random go fast parts at a good price, that really won't be the best performing engine because it was not planned out properly from the start. I'm talking from experience here. I am guilty of this. My engine was assembled and torn apart three times before I was satisfied and even fired it up. Now looking backward in time, if I could do it all over again, it would be totally different. Poor initial planning on my part.


I don't think you are being realistic about rebuilding your engine for $1500. I put together a very stout 350 Olds short block with custom pistons and a 330 steel crank. With parts and machine work I have close to $4000 into it. That does not include the core block and crank. The parts and labor ad up fast. I would recommend you find another engine to build and continue to enjoy your car as it is, until you're ready. Look for an earlier block without the windowed main webs. They are readily available. If you don't build the rest of your car to handle the horsepower, you will be breaking one thing after another. It will always come down to the weakest link. You might want to take a look at this thread-
https://classicoldsmobile.com/forums...e-gave-me.html
Coppercutlass has been wheelin' and dealin' to build a strong engine on the cheap. You might want to take a look at some of these builds and consider copying their recipe-
http://realoldspower.prophpbb.com/fo...91154d39623ceb
The best advice I can give you is to find a reputable Oldsmobile specialist, engine builder, that can help you with your project from beginning to end. If you would like some suggestions there's a short list on the first page of this thread-
https://classicoldsmobile.com/forums...cast-iron.html

1968CutlassSupreme

67 Cutlass Freak: I really appreciate your taking the time to reply, but with all due respect, this seems like an awful lot of money and time spent to gain about 100 or so horsepower. I don't want a drag car, just one that will roast the tires and run with most of the mustangs and camaros out there in the short run (light to light, 1/4 mile) and drive it around for fun.

I am not looking to rebuild the engine for $1500 - I am trying to keep the machine work to that or below. I plan to buy the flat top pistons outside of that figure (try to save the connecting rods and the crank), as well as the main, rod, and cam bearings, valves, springs, lifters, pushrods, cam, carb, intake and exhaust. I can buy all the parts as I can afford them, so long as I understand what parts to buy that are complimentary. This is the reason for the post. I cannot believe that I have to wait until I have $5000 to spend before I can begin buying parts for the build I am looking for...

67 Cutlass Freak

I took the time to reply because it sounded to me like you were not thinking through your entire project. First of all $4000 doesn't buy you much when it comes to an Oldsmobile performance engine. The small block that I built was built to run on race gas with high compression pistons. I think it will put out close to 450 HP. I don't think you fully understand how expensive it is to get that extra 100 HP out of your engine and make it live. I'm going to show you the list of what was put into my short block. This does not include heads, intake, distributor, oil pan, water pump, carburetor and a lot of other small misc parts needed. You might want to consider purchasing the 100 HP nitrous kit, which would be far less expensive than building a complete naturally aspirated engine capable of beating the new Mustangs or other late model sports car. Here's what I put into my short block:


Olds 350 CI Race Engine
1972 350CI engine block core
1967 330 steel crank core
1967 Flex plate
1972 Damper
JE Pistons Custom 2300077 $680.75
Rings J100F84080-5 $100.00
Rod bearings 02-5029 $60.00
Main Bearings MS805P20 $60.00
Rod bushings 02-5029 $40.00
(2) Heavy metal slug 1”X1” $70.00
ARP rod bolt RB-200 $58.00
Freeze plug kit FP-640 $14.00
Race Cam Bearings RCB-499 $69.00
Gasket Set GS-550 $95.00
High Volume Oil Pump SP-754 $69.00
Bolt on pick up PU-3 $35.00
J&S 5 Main Halo $250.00
J&S Main Stud kit $85.00
Custom modern grind cam/ lifters $265.00
Machine Work Performed by LAM Racing Engines
Install rod bushings, Fit/ assemble rods & pistons,
final polish rod beams, Recondition rods with ARP bolts-
includes R&R bolts, machine oil relief grooves in rods,
deck block, piston height + .0001,
Balance rotating assembly, regrind crank
Rods - .020 Mains - .020, install slugs of heavy metal (mill),
Install main studs, mill for main girdle (halo) to 2.175 depth of caps
Dial bore gauge main bearing bores, low limit to middle of spec,
Final wash block and install cam bearings & freeze plugs, check main
bearing clearance and ring end gaps. Total machine shop services - $1311
Final assembly and measurement performed by Dane Lulling of
Mild to Wild Racing $400
total investment- $3825.75

hookem horns

Just an idea, but do the minimal work you describe on the current 350 and buy/build a 455 on the side to swap when ready. A mildly built or even stock (pre-smog) one will still give tire roasting street performance over your current 350 even if well below your 400hp goal due to the gobs of low end torque. Keep saying I'm going to do this...

boese1978

OAI = Outside Air Intake as I recall.

1968CutlassSupreme

I get the impression that many of you (especially the experts on here) don't normally talk to people with as little knowledge as someone like me possesses. I bought this car as a tribute to my father, and I want to build it to be a strong street car as a tribute to my mother who used to spend a lot of time doing burnouts in her 72 charger (with a 318). I don't have the experience, though I have to begin somewhere and I am just trying to combine my tributary in one car (because I cannot afford more than one on a minister's salary ).

67 Cutlass Freak: You said "I don't think you fully understand how expensive it is to get that extra 100 HP out of your engine." You are absolutely right - and I said that in my reply to you. I thought that was very clear from the first. What is the motivation for one to rebuild at this cost when you can get a crate engine that puts out around 400hp out of box for less? Is it simply to keep an Olds engine under the hood?

I am going to show more of my ignorance right now - what is the benefit of having an olds engine over a chevy crate? Are Olds engines stronger? I truly want to understand and make the right choice - because I don't have tons of cash to throw around (which is why I am asking all of these questions in the first place).

Thank you, by the way, for your list - now I have something to look at as far as actual pieces to buy if I choose rather than "a cam, lifters, push rods, bearings...etc" which are all generic sounding to me (other than the cam which will come from cutlassefi).

Thank you all for your continued patience in helping a sentimental rookie toward his goal of accomplishing his paternal tribute! It means a lot to me.

oldcutlass

Keeping an Olds with an Olds engine is purely a personal choice. The purists are going to have one opinion and then some of us have another. No one is right, however the choice is yours. It will be much more expensive to put a Chevrolet engine in your Olds because your not considering the complete picture.


You will need all the accessory brackets for a Chev crate engine, you will need a Chev compatible transmission, torque convertor and starter, perform some wiring changes, new frame brackets and engine mounts and whatever other misc items to convert. Depending on transmission possibly another driveshaft and yoke. So as you can see it's not a simple swap unless you have all the parts already.


With that said, it's much simpler and less expensive to stick with your current engine in the long run.

jag1886

A lot of people (once again) throw around that 400HP# your engine didn't make anywhere near the HP it is advertised to have had, you are talking about adding a 140-150 more HP over the as installed engine had. I have seen a lot of people almost crap there pants over what a true 300HP engine with a proper gear behind it will do. If it's tribute car a good 300HP car will do all the burn outs the tires can stand. I also think it's real nice to be able to go out and drive the car when ever no matter what the weather is doing and it could even get pretty good gas milage. I have learned over the years it's more fun to tone down the performance (somewhat) and enjoy driving the car more.

pmathews

My modest build cost $3400, pistons were a little expensive as I needed the high compression ones from Egge, but aside from that and ARP bolts, 265DEH cam, springs and valves, it was mostly stock. I paid for some mild blueprinting, align hone, decking and milling, plus a first rate balance of the assembly, so my machining cost extra, but it's super smooth even with a lopey cam and 10.4 compression. Maybe I'm getting 325 hp? With 400 hp as a goal, $4000 sounds way too cheap unless you're doing all the labor and have a great relationship with your machine shop. A lot of guys on this board could pull that off, but not me (lol).

Fun71

Close: Outside Air Induction

Tim305

I am new to this site and this is only the second thread I've read. I must say I am very impressed by the quality of advice I see here. The original post was so close to what I was thinking about it could have been written by me. I found the advice very helpful and given by people who truly want to help. I'm not building a tribute car I'm trying to recapture my youth but I still love to do a good burnout. I think I found the right site here.

oldcutlass

Introduce yourself formally in the newbie forum.