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Okay fellas, so after tearing into my engine a little bit (350) I’ve decided to go with a general freshening up, plus some stuff to add a little more power.
The cylinders/pistons look to be in mint shape, and I believe they’d require minimum work to get them up to standards.
I would like to swap out bearings and rings as preventive maintenance, then camshaft and valve springs. Also it’s a given that I’ll be replacing all of the valves (at least 4 are bent, might as well do all of them), pushrods (bent), rocker arms and bridges (surface wear) and lifters because of the cam. Will also be installing new bolts and such (head bolts, etc.)
With that being said though, I need some help on deciding on a camshaft and what springs to go along with it. I don’t want to have something crazy, just something that will give me a little more pop in the low range around town, 1,500-5,000 rpm range. I’m new to this stuff so the numbers listed for cams confuse me a bit.. I don’t want to put it back incorrectly though and have a problem worse than what I started with.
Also, if I’m just having the block hot tanked with no boring, (will be honing myself before rebuild, don’t worry) do I get the original sized bearings to go with the aftermarket cam, being that the block won’t have any machine work done to it? Also same question with rods, I can just replace the bearings without new rod arms, right? Again I’m sorry for the newbie questions, just don’t know where to go to find a definite answer on things for the SBO. Not as convenient for us as it is those Chebby guys.
It's difficult to give a cam recommendation without knowing the engine's compression ratio, what vehicle it is (weight is a big factor), the rear gear ratio,etc.
I would like to swap out bearings and rings as preventive maintenance, then camshaft and valve springs. Also it’s a given that I’ll be replacing all of the valves (at least 4 are bent, might as well do all of them), pushrods (bent), rocker arms and bridges (surface wear) and lifters because of the cam. Will also be installing new bolts and such (head bolts, etc.)
Many of the valves may be fine, ask the machinist look at them first. Keep the old head bolts, some have studs for mounting accessories.
Also, if I’m just having the block hot tanked with no boring, (will be honing myself before rebuild, don’t worry) do I get the original sized bearings to go with the aftermarket cam, being that the block won’t have any machine work done to it? Pay close attention to the position and type of the block oil galley plugs before taking it to the machine shop. Consider removing them yourself, bagging and tagging them for re-installation to prevent oil pressure problems if the machine shop leaves them out, loses them or puts them back in the wrong positions. Consider having the machine shop do the de-glaze and hone, no disrespect meant but it needs to be done properly in order for the rings to seat and last.
Also same question with rods, I can just replace the bearings without new rod arms, right?
Yes, just bearings can and usually are replaced on a stock rebuild after determining the size(s) needed if the crankshaft needs grinding. If grinding isn't needed, still have it polished.
Put the savings from reusing parts that are excellent toward thinner head gaskets to avoid losing compression, a GOOD timing gear/chain set and having the distributor rebuilt and re-curved by someone with a Sun machine. About which cam and springs will be left to forum members that have way more experience and knowledge than me about those choices.
Thanks in advance for the help!
You are very welcome, good luck!!!
Last edited by Sugar Bear; November 4th, 2019 at 09:29 PM.
It's difficult to give a cam recommendation without knowing the engine's compression ratio, what vehicle it is (weight is a big factor), the rear gear ratio,etc.
It’s a 1968 Cutlass S, 350 2 barrel, st300 trans and I believe 2.73 gears. I think I read that the stock compression ratio would be somewhere around 9 to 1? It’s 100% how it was from the factory in 68. It does have #5 heads.
Most shops "bake" the blocks now days. Have the shop measure/machine hone cylinder bores if not to "loose", have them install new cam bearings. You might as well (over bore/new pistons) "bent valves, hmm" if so, you're looking at valve guides. Jmo, find a 403 and use your heads.
I would also swap in a TH350 with a Transgo shift kit. Also the base Jeggs torque converter 2000 to 2300 rpm stall would add off the line power. Just swapping the trans and converter will add noticeable power. The 214/214 .472/.472 110 LSA cam Cutlassefi worked well in my 9 to 1 Olds 350 with a 2300 stall(rated at 2200 to 2500 stall) and 2.78 gears.
I would also swap in a TH350 with a Transgo shift kit. Also the base Jeggs torque converter 2000 to 2300 rpm stall would add off the line power. Just swapping the trans and converter will add noticeable power. The 214/214 .472/.472 110 LSA cam Cutlassefi worked well in my 9 to 1 Olds 350 with a 2300 stall(rated at 2200 to 2500 stall) and 2.78 gears.
I plan on going to a TH350 at some point, could use the extra gear. Maybe trans will be next winter’s project lol. How well would this cam work? Just like that the kit comes with almost everything I need without worrying about messing up and getting the wrong spring strength, etc.
Also, could I use it with new OEM style rocker arms/pushrods?
I plan on going to a TH350 at some point, could use the extra gear. Maybe trans will be next winter’s project lol. How well would this cam work? Just like that the kit comes with almost everything I need without worrying about messing up and getting the wrong spring strength, etc.
Also, could I use it with new OEM style rocker arms/pushrods?
Just went back and looked at the measurements of the cam you talked about and compared with the one I posted, very similar.. right?
The 260h comp and the 268h comp are both great cams. I ran the 260 in a very mild stock like build and the car ran 13.86 in the 1/4 mile and was great on the street. Stock like idle.
The 260h comp and the 268h comp are both great cams. I ran the 260 in a very mild stock like build and the car ran 13.86 in the 1/4 mile and was great on the street. Stock like idle.
Damn! That’s about what I’m going for. Do they make a kit for that cam? Valve springs, lifters, etc?
sorry I’m a tad slow lol, same one in pic above correct?
I think tbr 268h is great if you have true 9 to 1 compression. I think your engine is realisticly closer to 8.5 to 1 but you have to measure cc chamber pistons dish and all that good stuff . i would run the 260h. It will put you on the safe size for your build.
I think tbr 268h is great if you have true 9 to 1 compression. I think your engine is realisticly closer to 8.5 to 1 but you have to measure cc chamber pistons dish and all that good stuff . i would run the 260h. It will put you on the safe size for your build.
You’re probably right about the compression. If it was 9-1 new, it’s not anymore lol. Do they sell a 260h grind as a kit as they do with the 268?
Your stock springs should be ok for that cam . but. Have a shop check them. The reality is the factory posted compression always varied and was rarely spot on to what was published. There is variances in piston to deck height , chamber CC's that can make that compression a +/- so unless you measure where its all at then play on the safe side.
The springs in my 7A heads are stock on that 260h cammed engine had 60k on the engine when I pulled them. Still in use 12 years after it was built. Im not saying they are expensive but if they check out its not the end of the world for an engine that wont spin past 5500 rpm. .
Well I agree with Mark. Back in 1982 I rebuilt the engine in my 1970 Supreme and the machine shop used the original springs. The engine would fall flat on its face if I tired to rev it over 5000 RPM. It would pull great to 5000, but would not go past that. I installed a set of new springs and voila, it would pull to 5500 RPM with ease. And those springs were only 12 years old, whereas here we're talking about 50 year old springs.
The springs in my 7A heads are stock on that 260h cammed engine had 60k on the engine when I pulled them. Still in use 12 years after it was built. Im not saying they are expensive but if they check out its not the end of the world for an engine that wont spin past 5500 rpm. .
That's like getting showered, getting all dressed up in your Sunday best and wearing dirty boxer shorts and smelly socks....MAKES NO SENSE not to do the job right!
That's like getting showered, getting all dressed up in your Sunday best and wearing dirty boxer shorts and smelly socks....MAKES NO SENSE not to do the job right!
New springs will be used! Sorry I wasn't very clear, I didn’t mean literally the same exact ones, but ones with the same amount of load, my apologies lol
He said he was gonna freshen up the engine usually this does not include a piston replacement or replacement of any parts that dont show major wear . Mild near stock using a 260h cam i wouldnt hesitate to reuse the old springs if they check out. Plus the stock pistons have their limits too. Again my 350 i mentioned with the 260h cam with those old valve springs powered my car to a 13.86 in the 1/4 mile i raced it 3 season then it went into my Pontiac which my wife drives and is going to race it with that 350 now too. So that's my first hand real experience with reusing the valve springs. Just fwiw. You gotta take it with a grain of salt.
@ajr2820 you gotta be a bit more descriptive because my 11 sec 355 is pretty much all used parts and hand me downs. It did get the correct valve springs but im spinning it to 7k Rpm. So that's like me showing up to the party dirty after work and still getting lucky ? Based off of your logic atleast.
This is nothing against Mark but his advice comes from having to sell parts and sell a job with some kind of warranty or atleast stand behind his work. In that respect i totally understand. For a novice hobbyist doing it themself if the springs check out then go for it. Swapping springs with the engine in the car is very easy if it needs them. Again take it with a grain of salt.
The one and only failure i have had with budget type builds was using some old factory cast flat tops with .005 piston to wall clearance. After 2 seasons of racing and lots of high RPMs I cracked 4 skirts.
Last edited by coppercutlass; November 5th, 2019 at 01:16 PM.
This is nothing against Mark but his advice comes from having to sell parts and sell a job with some kind of warranty or atleast stand behind his work. In that respect i totally understand. For a novice hobbyist doing it themself if the springs check out then go for it. Swapping springs with the engine in the car is very easy if it needs them. Again take it with a grain of salt.
Thats a helluva thing to say. How many people have I helped on here FOR FREE!!!!
I don’t HAVE to sell anything. And I just mentioned replacing them, NEVER said anything about selling him any springs or anything else for that matter, for any reason other than it’s a very good idea to do so.
I thought we got passed this stuff, apparently not.
Thank you.
Last edited by cutlassefi; November 5th, 2019 at 01:47 PM.
He said he was gonna freshen up the engine usually this does not include a piston replacement or replacement of any parts that dont show major wear . Mild near stock using a 260h cam i wouldnt hesitate to reuse the old springs if they check out. Plus the stock pistons have their limits too. Again my 350 i mentioned with the 260h cam with those old valve springs powered my car to a 13.86 in the 1/4 mile i raced it 3 season then it went into my Pontiac which my wife drives and is going to race it with that 350 now too. So that's my first hand real experience with reusing the valve springs. Just fwiw. You gotta take it with a grain of salt.
@ajr2820 you gotta be a bit more descriptive because my 11 sec 355 is pretty much all used parts and hand me downs. It did get the correct valve springs but im spinning it to 7k Rpm. So that's like me showing up to the party dirty after work and still getting lucky ? Based off of your logic atleast.
This is nothing against Mark but his advice comes from having to sell parts and sell a job with some kind of warranty or atleast stand behind his work. In that respect i totally understand. For a novice hobbyist doing it themself if the springs check out then go for it. Swapping springs with the engine in the car is very easy if it needs them. Again take it with a grain of salt.
The one and only failure i have had with budget type builds was using some old factory cast flat tops with .005 piston to wall clearance. After 2 seasons of racing and lots of high RPMs I cracked 4 skirts.
Good deal, thanks man I appreciate the advice. And yeah, most definitely not going for a 100% professionally built engine.. nor do I want a gas sucking 8 sec quarter mile beast either. I’ll save that for another car lol. To be honest, this engine really needs very little, and could have gone for another 50k with just work on the top end.. I busted into the bottom end today and it is mint. Does not at all look like an almost 100k mile motor at all. But, me being thorough if it’s pulled and apart, I’d like to do it the best I can while I’m into it in my garage at home.. While not put 5k into it. It’s been a tremendous learning experience as well. Just want to have something that will make the pretty girls at the stoplight laugh.. lol
Most shops "bake" the blocks now days. Have the shop measure/machine hone cylinder bores if not to "loose", have them install new cam bearings. You might as well (over bore/new pistons) "bent valves, hmm" if so, you're looking at valve guides. Jmo, find a 403 and use your heads.
I’d totally be up for a new block, but I’d feel terrible just tossing the old one. It’s really in great condition. 3/4 of the cylinders don’t even have the ring lip. Which I guess is good, unless the rings aren't doing their job lol
With the lousy 2 spd trans without the switch pitch converter, I believe the 68 no longer were. It will be no powerhouse. My my daughter fried the 2004R trans with a 2200 to 2500 stall I put in my 70S, converter flashed at 2300 rpm. I went back to the TH350 with the factory 1600 to 1700 stall with the same 2.78 gears. I went from 1/4 block burnouts to spinning tires only if everything is perfect at launch. That is a 9 to 1 350, 214/214 cam, TH350 and 2.78 gears. That Comp 260H is as big as you want to go for now. If you are adding a 4 bbl, don't buy an Edelbrock carb and dual exhaust, that will help for sure. While the heads are getting rebuilt, get them milled enough for true 9 to 1 compression. The stock 14cc pistons will be .025 to .030" below deck with .041" Felpro head gaskets, 60cc combustion chambers are needed for 9 to 1. Good luck.
With the lousy 2 spd trans without the switch pitch converter, I believe the 68 no longer were. It will be no powerhouse. My my daughter fried the 2004R trans with a 2200 to 2500 stall I put in my 70S, converter flashed at 2300 rpm. I went back to the TH350 with the factory 1600 to 1700 stall with the same 2.78 gears. I went from 1/4 block burnouts to spinning tires only if everything is perfect at launch. That is a 9 to 1 350, 214/214 cam, TH350 and 2.78 gears. That Comp 260H is as big as you want to go for now. If you are adding a 4 bbl, don't buy an Edelbrock carb and dual exhaust, that will help for sure. While the heads are getting rebuilt, get them milled enough for true 9 to 1 compression. The stock 14cc pistons will be .025 to .030" below deck with .041" Felpro head gaskets, 60cc combustion chambers are needed for 9 to 1. Good luck.
Good deal. Thanks for the help! I plan on switching out the trans at some point and gears at the same time.. Maybe that’ll be next winter’s project (if I don’t blow it up sooner lol.) But really, I don’t drive it hard and I kind of enjoy the gears being how much highway driving I do. Was getting around 20 mpg over the summer. But for now, it’ll get a Qjet and Hooker long tubes. I’ll see how it does with the stock converter for now and if it doesn't work out I can put that in after the rebuild. If you don’t mind me asking, what is a switch pitch converter? I hadn't heard if that before.
Actually a 2004R is ideal but that costs more to build and also needs a rear gear swap. Best of both worlds more acceleration, better 2.74 first gear and good fuel economy even with a 3.42 gear, .67 overdrive and lock up converter drop highway rpm by about 1000 rpm. My 88 Cutlass with a 2004R, 3.42 gear and 225/70R14 gears runs 1900 rpm at just under 70 mph. Also bolts right in but is definitely the most expensive. Another consideration is the TH350C, from 1981 to 1986. It fits right where your current trans is and the lock up torque converter drops rpm around 300. If you are fine with your current highway rpm then a regular TH350 will work fine. The torque converters are cheaper than the TH350C and the Transgo kit allows dual feed the direct clutches. The TH400 requires a different drive shaft yoke and maybe cutting the drive shaft even with the shortest tail shaft 400. It is overkill for your mild build, the TH350 can built plenty strong for your mild build.
Actually a 2004R is ideal but that costs more to build and also needs a rear gear swap. Best of both worlds more acceleration, better 2.74 first gear and good fuel economy even with a 3.42 gear, .67 overdrive and lock up converter drop highway rpm by about 1000 rpm. My 88 Cutlass with a 2004R, 3.42 gear and 225/70R14 gears runs 1900 rpm at just under 70 mph. Also bolts right in but is definitely the most expensive. Another consideration is the TH350C, from 1981 to 1986. It fits right where your current trans is and the lock up torque converter drops rpm around 300. If you are fine with your current highway rpm then a regular TH350 will work fine. The torque converters are cheaper than the TH350C and the Transgo kit allows dual feed the direct clutches. The TH400 requires a different drive shaft yoke and maybe cutting the drive shaft even with the shortest tail shaft 400. It is overkill for your mild build, the TH350 can built plenty strong for your mild build.
Awesome I’ll keep all of that in mind, thanks! I appreciate it
November 4th, 2019, 07:32 PM
