Small block performance
April 19th, 2018, 02:32 PM
#1
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Thread Starter
Join Date: Apr 2018
Posts: 7
Small block performance
hi guys—
i have a 70 cutlass supreme convertible that I would like to perk up just a little. I will be installing headers (that was last night’s question).
I have a holley 650 double pumper laying around with about 50 miles on it. I was planning on installing an Edelbrock performer or performer rpm intake and then a cam. The main question for now is which manifold? I don’t care about top-end speed. I just want a tire scorcher. I’m sure I have left out a lot of info, which I am more than happy to provide. It is stock right now with a th350 and quadrojet. Not sure about the rear end, but I would guess in the 2’s, not 3’s.
i have a 70 cutlass supreme convertible that I would like to perk up just a little. I will be installing headers (that was last night’s question).
I have a holley 650 double pumper laying around with about 50 miles on it. I was planning on installing an Edelbrock performer or performer rpm intake and then a cam. The main question for now is which manifold? I don’t care about top-end speed. I just want a tire scorcher. I’m sure I have left out a lot of info, which I am more than happy to provide. It is stock right now with a th350 and quadrojet. Not sure about the rear end, but I would guess in the 2’s, not 3’s.
April 19th, 2018, 04:20 PM
#3
Registered User
Thread Starter
Join Date: Apr 2018
Posts: 7
Small block performance
thank you—
i am looking to improve performance before doing a rear-end swap. I guess the question is which manifold will provide more get-up-and go? One with a higher plenum or one closer to the stock height?
i am looking to improve performance before doing a rear-end swap. I guess the question is which manifold will provide more get-up-and go? One with a higher plenum or one closer to the stock height?
April 19th, 2018, 04:42 PM
#4
Registered User
Join Date: Jun 2014
Location: Ft. Wayne, IN
Posts: 1,195
Welcome to CO. Pics of your ride would be WELCOME!
Edlebrock puts the "RPM" in "Performer RPM" for a reason: It's tuned for higher RPM HP rather than low-end torque. If all you need is to burn rubber and have a peppy car around town, the Performer would work fine. If you are going for that high trap speed in the 1/4-mile, you'll regret not getting the RPM.
As always, the cam must be matched to the intake for optimum performance, so it makes no sense to change the intake w/o doing the cam (& lifters) at the same time. If you go w/ the RPM, you'll want to choose a higher stall TC and rear gear to take advantage of that newfound HP. The cam also has to be matched to the compression ratio, so assuming your 350 came stock w/ the 4 bbl and is still wearing the original heads, you should have around 10:1 CR. There are others on CO that know way more about choosing a cam for a given combination than I, I'm sure they'll be chomping at the bit to provide guidance there.
Edlebrock puts the "RPM" in "Performer RPM" for a reason: It's tuned for higher RPM HP rather than low-end torque. If all you need is to burn rubber and have a peppy car around town, the Performer would work fine. If you are going for that high trap speed in the 1/4-mile, you'll regret not getting the RPM.
As always, the cam must be matched to the intake for optimum performance, so it makes no sense to change the intake w/o doing the cam (& lifters) at the same time. If you go w/ the RPM, you'll want to choose a higher stall TC and rear gear to take advantage of that newfound HP. The cam also has to be matched to the compression ratio, so assuming your 350 came stock w/ the 4 bbl and is still wearing the original heads, you should have around 10:1 CR. There are others on CO that know way more about choosing a cam for a given combination than I, I'm sure they'll be chomping at the bit to provide guidance there.
Last edited by JohnnyBs68S; April 19th, 2018 at 04:53 PM.
April 20th, 2018, 08:17 AM
#7
Maintained
Join Date: Oct 2015
Location: Calgary, AB.
Posts: 576
you probably won't notice much improvement by just doing some engine mods alone. chances are good you may even feel your car has lost power after engine mods when your still running the same highway rear gears and stock torque convertor.
April 20th, 2018, 02:20 PM
#8
Old(s) Fart
Join Date: Mar 2007
Location: Northern VA
Posts: 47,301
As others have pointed out, the car needs to work as a system. Simply changing the intake will be a disappointment. A double pumper is a poor choice on an otherwise stock vehicle. The Qjet will be crisper off the line, plus it's a 750 CFM carb. Why go smaller?
April 21st, 2018, 11:24 AM
#9
Registered User
Join Date: Mar 2013
Location: St. Clair, MI
Posts: 1,647
A good performance tune up should allow the car to burn rubber all day long. Ive had several 4bbl 350 Cutlass' and Cutlass Supreme with 2.56 and 2.76 gearing that had no issues with spinning the tire on dry pavement. Install new points,cap,rotor,plugs, and wires. Bump the timing a few degrees from stock. Clean and adjust the QJet(buy a book on adjusting the carb properly). I find that most 40 year old cars are way out of tune unless their owner was a mechanic or had a friend who was.
April 21st, 2018, 01:26 PM
#10
Hookers under Hood
Join Date: Nov 2013
Location: Ontario, Canada
Posts: 3,543
A tune and timing couldn't hurt, but I have to agree with others on the rear gears .
I had a smog 1976 350 without the HP you have. Prior to joining Classic Olds , I put an Edelbrock Perfomer intake, 600 CFM eddy carb, 2" duals , K&N filter, Shift kit in the trans, and still didn't feel much. The duals helped, but the intake and carb was a waist on my stock engine. Weight reduction was about it.
Came to Classic Olds, asked a similar question, they mentioned rear gears, and " BANG" best money I ever spent!!
I went from 2:41 to a new carrier and 3:42 , whole different animal !!
Take the advice above , don't buy the intake and engine stuff yet or you will be disappointed same as I was.
Purchase the intake when you have the rear gears and Torque converter picked out with the cam etc.
Awesome guys here....Take their advice !!
Eric
I had a smog 1976 350 without the HP you have. Prior to joining Classic Olds , I put an Edelbrock Perfomer intake, 600 CFM eddy carb, 2" duals , K&N filter, Shift kit in the trans, and still didn't feel much. The duals helped, but the intake and carb was a waist on my stock engine. Weight reduction was about it.
Came to Classic Olds, asked a similar question, they mentioned rear gears, and " BANG" best money I ever spent!!
I went from 2:41 to a new carrier and 3:42 , whole different animal !!
Take the advice above , don't buy the intake and engine stuff yet or you will be disappointed same as I was.
Purchase the intake when you have the rear gears and Torque converter picked out with the cam etc.
Awesome guys here....Take their advice !!
Eric
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