would a 375 be to much for a '72 rocket 350?

Andrew Brian
65

Asked by Andrew Sep 10, 2009 at 11:49 AM about the 1972 Oldsmobile Cutlass Supreme

Question type: Car Customization

if i were to put a new cam in my olds 350 rocket, would a 375 be to much? i want the car to sound good but its a daily driver & i dont want it to swallow gas by the gallon.

17 Answers

Ken Rinear
75

I am not sure what you mean by a 375. Are you talking Crane, Comp Cams, etc.? My advice is to leave it alone! I changed the cam in my original 350 years ago and it blew up the radiator and the cooling system. You really have to know what you are doing and have an expectation of the cost involved. The best way to make the car sound good is to replace the exhaust system with a 2-1/2" aluminized or stainless steel system with Flowmasters. You'll get the sound and good performance. You did not say whether your car was a 4 or 2 barrel. As far as your trans goes, it is most likeley a TH-350. Unless you have a 442 with a 455 you are not likely to have a TH-400. You never know though since things get swapped out over the years. If you look at the right side for a plate that goes something like OD on some similar letters you would have a TH-400, but again it is not very likely. Fee free to contact me on my page if you need other help. Best regards, Ken.

Andrew Brian
65

well right now it is a 2 bbl. but i am eventually going to change it to a 4 bbl. & is an auto transmission. i want a louder & a little bit more umpff to the sound but not too much, just to get more attention.

Andrew Brian
65

and yes i was talking about crane cams, comp cams. do you really think that it would be best is if left it stock? i mean i want a daily driver that sounds good but won't blow up and be a year long project. i have a boat that is already being re-done agin. haha

1 out of 1 people think this is helpful.
Bill Dana
45

i have a 71 cutlass with a 350 that i put a cam intake and headers and exhaust on. a performer intake with a matching cam and full exhaust through mufflers will sound good run good and bring you no issues with drivability. the key is to carefully match the cam to everything else. headers would be best on it but they are frankly a pain in the ass if you do the work yourself. with cams bigger is not always better, cams usually apply to a certain compression ratio and rear gear ratio.all of this you can find in summitracing.com so for best performance you'd be best getting a performer intake(PN EDL-3711), a 600cfm holley(PN HLY-0-1850C) and a performer cam(PN EDL-3712), and if someone else is doing the work id recoment headers(sounds louder with headers and exhaust than just exhaust alone). and flowmasters definitly have a good sound (PN FLO-17119with mufflers, PN FLO-17107 without mufflers), if you want louder go with dynomax ultra flo Bullets(PN WLK-24215) hope this helps

1 out of 1 people think this is helpful.
Andrew Brian
65

yea it helps alot but what size cam did you put in? i dont want to have to change the push-rods & a bunch of other stuff b/c moneys a crunch 4 me lol would i be able 2 keep the same stock headers if i put a 280 cam in it?

Jim Schardinger
5

Hi, 1st of all ....Watch out.. and how many miles are on that precious motor? Dropping a heavy cam on her will ruin you bearings.. At most even from factory 3.08 for a 350 (cid) is a reach. 3.28 for a 455(cid) .. Doesn't sound like a much of a difference,...And this isn't a weekend job... Is you Cutlass a 2 Barrel? ...I ask 'cause you didn't mention that.. Oh yeah ..That makes a difference. Your fooling around with all kinds of mixtures. Why do want to change the cam? Is it worn? How do we know this?.... Your saying a 375? that turning is for a Cadillac 472 0r a 502. Yeah there use to an engine 500+ cubic inches.. Not a crate motor.. But from Michigan, actually... Pontiac, Mi.. era '70-73... Jim

Andrew Brian
65

ive got 50,000 miles, yes it is a 2barrel but i am going to put a 4 barrel on it, would you suggest leaving the stock cam in it?

Bill Dana
45

well basically i have a .490/.490 230/230(@.050) cam from comp cams. its a little much for my rear gear ratio. the stock cam is less performance oriented but will work fine if you used a 4 barrel intake. i changed my cam and had no bearing issues what so ever. the duration is what you need to watch out for, 2 valve pushrod motors want more lift versus duration which is why roller cams are best for performance. but with a mild build a small cam like the edelbrock one will give you a bit more top end pull and you shouldnt have to change your whole valvetrain. i have stock replacement pushrods in my 350. the thing i would recomend changing are the lifters (and springs if the budget permits) your car sounds ver very similar to what i started with. i had a 350 2 barrel olds with single exhaust and freeway gears(i cruise at 2200 at 70) at this moment i have a performer RPM intake, that cam that i previously specified a 600 holley a set of doug thorley headers. the internals are new but that is because i had blew a hole through the air filter lid(you know the ones with the filter on the top) and had been sucking dirt into my motor for 6 months till i noticed the oil from the rear main. but anyways if you are retaining the stock 2 barrel setup and have single exhaust the cam change will most likely hurt you. if you switch to freer flowing exhaust and intake then the next step is the cam.

Andrew Brian
65

no i have dual exaust, the previous owner put the 2 barrel on it (like an idiot) haha but its working for now but i am going to put a 4 barrel back on probably 6 or 700 cfm

Bill Dana
45

oh good exhaust is half the battle, just put a performer intake on and a 600. a 700 might be too much carb for the motor without a cam or head work and a performer intake wont need that much air either. usually if you put too big of a carb you lose all your bottom end torque and if everything else doesnt match the carb size then your top end doesnt even gain anything. the key to a good setup is to have everything match not to have the biggest of everything. cam and carb are 2 things that smaller ends up being better. and also the advantage to a 4 barrel holley is the primary 2 barrels will be the only ones in use if you are light on the gas, so you use only 300 cfm instead of the Rochester 2 barrel that is 500cfm, so if you dont have a heavy right foot you should get better gas milage.

Bill Dana
45

this was my car when i bought it lol

Andrew Brian
65

I love the car! haha and yes the carb is a rochester 2barrel but when i put the 4 barrel on, should i go with the rochester since they were the stock carbs? if not what do you recomend? thank you for all the info you have shared, it has been a Huge help!

Bill Dana
45

oh no problem man, im on here to help ppl with oldsmobiles, seems like they are becoming rarely seen under the modified catagory. which is why i choose to build a twin turbo 455 and see where that takes me lol but yeah if you want a somewhat factory correct car go with the rochester but if i were to pick id go holley because they are rather simple and easy to fix if needed. rochesters are a bit more complicated, but then again i have never approached building one, although i have heard they are very good street carburators because of their small primary barrels. oh and yeah if your into figuring out holleys , you can usually pick one up at a swap meet(600cfm 1850 style) for cheap(ive bought some as cheap as 25 bucks) and then throw new floats and gaskets in it and your good to go for about 75 bucks. just need to know factory jeting and how to adjust the float. assuming you buy one that hasnt been messed with.

Kyle Budke
25

keep it original man, belive me your gunna want to

Cory Soczka
35

What i would is look up the specs for the stock cam and go from there. Other thing is If you do have a legit rocket 350 egine, it should have a decent cam in already. For a 4 bbl setup, I would go the route with the Edelbrock performer intake with the Edelbrock #1406 carbureator (600 cfm electric choke). Then go look at Dynomaxx Blackjack Headers. I have this combo on my '82 Cutlass, only mine is a chevy setup.

1 out of 1 people think this is helpful.
Bill Dana
45

ewww chevy in an olds.... stock cams arent very performance oriented unless you have a ram rod 350 or the cam out of a big block... trust me, my setup will burn that chevy in the 82 cutlass

bluRAYwhale
145

re: "would a 375 be to much "cam" for my 1972 Oldsmobile 350 motor". There is no mystery to this, its simple. Cams dont "blow-up" motors, Olds. motors "like" alot of cam. These motors are "special". Stock cams this and that, W-30's, 27's and 25's. O K you got a basically stock motor, '72 right? 8.5 to 1 Comp. No EGR and you want to run it on the street, start in the mornings even if its ten below zero outside, get good fuel economy(18-20 mpg). The car has an auto trans, power brakes, A/C controls and other assorted(emmision controls), factory vacuum operated stuff(GM power brakes w/vacuum assist need at least 15" of vac.). You don't want to spend a "ton" of $ on aftermarket stuff and all the associated time that goes along with making it all work. Its got to be reliable so you can drive it anywhere, and if need be a mechanic has to be willing to do repairs and adjustments on the motor. There is no computer controls so you got to do the thinking for the motor. Get a Crower camshaft, call the company and follow their suggestions, I'd say a single pattern with a 110/112 degr. seperation, .405" lift on the intake and about the same on the exaust. You didn't mention stall speed, rear gearing, tire diam. Anyways forget 375HP from a small Olds. get a "F" block 455 with some "G" or "Ga" code heads, re-work the whole deal, put a specially built TH350(you're goining to need it), behind it and let 'er rip. Or go the long route and put in the legendary TH400, you'll need two 455's to screw one of those up. Have fun.

1 out of 1 people think this is helpful.

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