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Discussion Starter · #1 ·
I have a chevy 350 on standard bores and flat top pistons (no valve reliefs).
I`m thinking of going with 64cc vortec heads (cr around 10:1) but am not sure which cam,intake,carb combination to use.
It`s going in a 2200lb car which will be used mainly for the street with occasional track use.
A slight uneven idle isn`t a problem.
I`m looking for around 350 hp and plenty of power from fairly well down the rev range (I`m not looking for a high revving racer)

Anybody got any suggestions?
 

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I would just go to comp cams web site and look at there cams, it should tell you what cam you need to get the results you seek. I would use a Edelbrock performer RPM intake or the like. A Demon, Holley, or Edelbrock 750 carb, any will suit your needs. with a vehicle only weighting 2200lbs it should be a outstanding runner.
 

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Paul, depends alot on what RPM you plan to see. What gearing ? automatic or stick ? what car is this ? just curious ? when you say track, do you mean drag race ? or other ?is it a cast piston engine ? stock bottom end ?
 

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Vortec heads with stock springs limit your lift to .475-.480. With what you want, I would go with a Performer intake and a 600 cfm carb. For a camshaft, I'd go with a XE262 or you could follow the 330hp 350 from GM Performance. Here is their specs: complete crate engine in the form of a 350 cubic inch HO with approximately 9.1:1 compression, 330 horsepower at 5000 rpm and 380 ft./lbs. of torque at 3800 rpm. These 4-bolt main engines have a recommended max RPM of 5500. Dressed to impress with chrome valve covers and front timing cover these engines will look great between the fenders of your favorite street rod, muscle car or grass roots racer. These 350 HO are not intended for marine use and should only be used in 1979 and earlier pre-emissions street vehicles or any year off road vehicles. Parts used in this engine assemblies are 4-bolt main 1-piece rear main seal blocks, nodular cast iron crankshafts, powdered metal connecting rods, Dished cast aluminum pistons. Installed camshafts are hydraulic flat tappet with .435 in. intake lift and .460 in exhaust lift with duration at .050 in. for intake is 212 and 222 for exhaust with a 112.5 lobe centerline. Standard morse link timing chains are installed. Cylinder heads are Vortec cast iron style with 64cc chambers; 170cc intake runners with 1.94 in. intake valves and 1.50 in. exhaust valves. Stamped steel self-aligning rocker arms are used for reliability. Aluminum dual plane with EGR capability Vortec style intake manifold with a Holley 600 CFM vacuum secondary with electric choke help feed the engines. Spark plugs, HEI distributors, and spark plug wires are included. Cast iron long style water pumps with standard "V" belt rotation threaded for 79'-89' power steering pump brackets. Standard 8 in. balancer and 12 3/4 in. flexplates, along with chrome air cleaner, and standard cast aluminum thermostat housings with driver side hose connection and a 180 degree thermostat. This kit also includes the oil filter, oil filter adapter, pcv valve, pcv hose, oil dipstick, and tube. Does not include starter, fuel pump, fuel pump push rod or the fuel pump adapter plate.


I went with a little bigger camshaft since you got more compression. With about 350hp in 220lb car, that would be a fun ride. Good luck
 

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Discussion Starter · #6 · (Edited)
stepside454 said:
Paul, depends alot on what RPM you plan to see. What gearing ? automatic or stick ? what car is this ? just curious ? when you say track, do you mean drag race ? or other ?is it a cast piston engine ? stock bottom end ?
I won`t need to rev any higher than 6000 revs.
Stick shift 3.058 rear end (Jaguar xjs)
Car is an AC Cobra replica (Don`t slate me please - I know it should really be ford powered :rolleyes: )
By track I mean trackdays (with bendy bits ;) ) but I can`t rule out the occasional day at the drag strip.
Yes cast pistons and stock crank/ rods.
The only thing I was thinking of upgrading on the bottom end was to ARP bolts.

tornado-tech said:
Vortec heads with stock springs limit your lift to .475-.480. With what you want, I would go with a Performer intake and a 600 cfm carb. For a camshaft, I'd go with a XE262 or you could follow the 330hp 350 from GM Performance. Here is their specs: complete crate engine in the form of a 350 cubic inch HO with approximately 9.1:1 compression, 330 horsepower at 5000 rpm and 380 ft./lbs. of torque at 3800 rpm. These 4-bolt main engines have a recommended max RPM of 5500. Dressed to impress with chrome valve covers and front timing cover these engines will look great between the fenders of your favorite street rod, muscle car or grass roots racer. These 350 HO are not intended for marine use and should only be used in 1979 and earlier pre-emissions street vehicles or any year off road vehicles. Parts used in this engine assemblies are 4-bolt main 1-piece rear main seal blocks, nodular cast iron crankshafts, powdered metal connecting rods, Dished cast aluminum pistons. Installed camshafts are hydraulic flat tappet with .435 in. intake lift and .460 in exhaust lift with duration at .050 in. for intake is 212 and 222 for exhaust with a 112.5 lobe centerline. Standard morse link timing chains are installed. Cylinder heads are Vortec cast iron style with 64cc chambers; 170cc intake runners with 1.94 in. intake valves and 1.50 in. exhaust valves. Stamped steel self-aligning rocker arms are used for reliability. Aluminum dual plane with EGR capability Vortec style intake manifold with a Holley 600 CFM vacuum secondary with electric choke help feed the engines. Spark plugs, HEI distributors, and spark plug wires are included. Cast iron long style water pumps with standard "V" belt rotation threaded for 79'-89' power steering pump brackets. Standard 8 in. balancer and 12 3/4 in. flexplates, along with chrome air cleaner, and standard cast aluminum thermostat housings with driver side hose connection and a 180 degree thermostat. This kit also includes the oil filter, oil filter adapter, pcv valve, pcv hose, oil dipstick, and tube. Does not include starter, fuel pump, fuel pump push rod or the fuel pump adapter plate.


I went with a little bigger camshaft since you got more compression. With about 350hp in 220lb car, that would be a fun ride. Good luck
I have seen there is an upgraded vortec head available from Scoggin Dickey that will take up to 0.530" lift - what cam would you recommend to use with these heads?
Or would it be maybe better to order bare vortec heads and comp cams K-Kit (pricy) and a set of valves/rockers?
 

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I would go with the Scroggin Dickey heads if you are looking at a bigger cam. They have an excellent kit for the money with the upgraded heads, gaskets, bolt and a Performer RPM intake for $909.95. If you want the heads bare and assemble them, it will probably cost you more to get them done since it will require machining to get a bigger spring in them. I would go with a xe274 cam and a Holley 650 double pumper. The smaller double pumper will give you excellent throttle response to get out of the corners. When you start getting into bigger lifts, you will need to check valve to piston clearance.
 

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Since your using stock pistons etc. Id keep the RPMS under 6K. As far as camshaft, I assume your using hyd. flat tappet. Id use Comp Cams 275 DEH 219/229 @ .050 .462/.482 lift 110 LSA .
For an intake, normally Id suggest Edelbrock Performer or Wieand Action + for this RPM range, but since your car is so light, the RPM may work well to.for a carb Id stay in the 600-625 CFM range. John
 

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carburetor

If all you are going to turn is 6000 RPM, the Performer or another intake similar to it and a 600 CFM carb is plenty sufficient. You would have a hard time using all of a 750 on that engine, and I think you would find your lower end power and your gas mileage will be better as well with the 600. I have done some vertual dyno testing with different sized carbs and on engines in the 5.8 liter area; 350's and 351's, you will only see some marginal gains with the 750 when over 5000 rpm, and at peak it only amounts to 5-6 hp increase.
I totally concur with stepside454 on this one.

Ill forgive you for the Heresy of putting a Chevy engine in a Cobra, since its a replica. Were you to have done that to a real Cobra, I would have demanded execution at dawn. LOL.

Using the CFM formula, I have discovered that for engines in that 350/351 size, that for every 1000 rpm you desire, 100 CFM will get the job done. Since a 350 at 6000 rpm only requires 608 CFM, I would say that you cant get much closer than a 600. Sides its always better in those cases to err to the more conservative side.

IF a little bit is good, it doesnt necessarily mean a lot is gooder.
 

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Discussion Starter · #11 ·
Thanks for all the advice guys.
The mist is starting to clear now :rolleyes:

It looks like.
Uprated Vortec heads
Edelbrock Performer RPM intake
Comp Cams 275 DEH 219/229 @ .050 .462/.482 lift 110 LSA
Only stuck on the carb
750 vac. secondary or 650 double pumper - what differences would I see/feel between the 2?
 

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Discussion Starter · #13 ·
stepside454 said:
I lean towards the smaller carb, the 750 will work, but in my opinion, overall the smaller carb will work better, I personally would use a 600 or 625 vac. sec.
I`ve just been reading on the Holley site and you are right - 600cfm should be adequate although they lean towards a 650. They also recommend mechanical secondary for a light car using stick shift - one downfall being economy.
 

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600 vs 750

If you are going to run a 750, I would definately make it a vacuum job, and set the secondary vacuum spring to start opening between 3000 &3500 rpm. Running a mechanical secondary on the street can really be a pain, both in gas mileage and performance, as that large of carburetor, when sticking your foot through the firewall will actually kill your fuel air flow in the lower rpm's, especially below 3500, even with a stick.
To utilize all of that carburetor, you will have to be able to turn 7400 rpm, and you can easily do that with a 600 CFM.
I had a 57 pro street Anglia, with a 351 W running Twisted Wedge heads. Ive had it up to the 8000 rpm limit of the tach with a 600 CFM carb and never had a problem with it starving.
 

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The 750 will work fine. Just tune the secondaries in with the spring kit. The 750 will give you room for imrovement in the future.

I ran a 750 vac. on my slightly more than stock Ford 302. It ran great. It didn't like the 650 dp.
 
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