Interesting article for Gen 1 small block owners.

[Case75]

I found this article from the October 2009 issue of Super Chevy detailing the best bang for the bucks parts from over 1000 dyno pulls.

http://www.superchevy.com/technical/engines_drivetrain/completebuilds_testing/sucp_0312_dm15/

The best combo: 355 block, GM iron Vortec 64cc combustion chamber heads with 1.94/1.50 valves and 170cc intake runners, Comp Cams Magnum roller tip 1.6 ratio rackers (which I'm currently running), Edelbrock Performer RPM Air Gap Vortec intake (close to my current Performer RPM intake) and a Comp Cams Extreme Energy XE262H cam (218/224 @.050 .462/.469 lift ((1.5 ratio)) 110 LSA)

The result: 416HP @ 5600RPM and 440 lbs/ft of TQ @ 4600 RPM!!

The best part is the engine averaged 417 lbs/ft of TQ! All on pump gas. And with 17 HG of vacuum at 700 RPM according to the specs on Comp Cams website for that cam.

This is a very affordable build...now if I just had a good 4-bolt block kicking around.

 

[buckhorn76]

i believe the heads on that build are the scoggin-dickey prepped vortecs greg. the stock vortec heads won't take a cam with much lift without machining the spring seats and changing the spring diameter or using beehive style springs. scoggin-dickey heads are drilled and tapped for screw in studs as well. the intake manifold and valve covers differ from the gen 1 bolt patterns also. that having been said, the vortecs are excellent heads and make good power. the 64cc chambers will up the comp. ratio of your l48 to about 9.4-1 . i have been looking at edelbrock's e-street aluminum heads, i like the specs on them and they are well priced at about 910 bucks a pair. performanceparts.com stocks em. :seeya: p.s. summit racing's k-1103 cam and lifter kit is a good deal at 90 bucks.

 

[Case75]

Comps web site states that that cam kit will require machining of the heads for the valve springs: 12-238-2 - XTREME Energy? Hydraulic Flat Tappet Camshafts

Still, some impressive numbers.

And I agree, those E-street heads look like a real good value. I've been looking at them as well.

 

[Case75]

Interesting article here Vortec Cylinder Heads about these Chevrolet Performance Vortec Small Port Bowtie Cylinder Heads 25534421 - SummitRacing.com new GM Performance Vortec Bowtie cast iron heads which accept both perimeter and center bolt valve covers, performed better than the aluminum fast burn heads and will handle up to .530 valve lift. Other than the weight, they're just as good as the aluminum fast burn heads and better than the aluminum ZZ4 heads.

 

[buckhorn76]

those are good heads greg. the spark plug is not angled so your current headers will work but you will still need a new intake manifold. hood clearance can be a problem on our c3's and the vortecs and manifolds are higher than gen 1 style. they are a little pricey when compared to the e-streets. did you check out summit's k-1103 cam and lifters ? i plan on using a new goodwrench 350 [ about 1600 bucks ] the e-street heads, and the k-1103. should be decent performance ,inexpensive, and work well with my stock converter and 3.08 gear. check out mcmaster pontiac buick in orangeville. they are a gm performance parts dealer and deal alot with racers, their pricing is good. do you have a gm performance parts catalogue ? :seeya: doug.

 

[Case75]

No, I don't have their catalogue. On another C3 forum I belong to , lot's of guys using the vortec heads and intakes. There's more hood clearance on '73 and up models. You just can't use the stock air cleaner. Edelbrock has the best selection of Vortec intakes. None of their Vortec intakes measures any higher than the Performer RPM 55-86 intake I'm currently running and I can still fit a 14X3 air cleaner.

I looked at the Summit cam. Similar specs to the XE262H; 2 degrees more LSA and less lift and duration on the intake valve.

Are you planning on using roller rockers Doug? Sounds like you're going to have a good combination there.

 

[buckhorn76]

for me greg, the jury is still out on choice of rockers. the engine will rarely see the north side of 5000 rpm. i am thinking i may just go with stamped steel 1.5's. my goal is only to equal the performance that that one might have had on a pre-smog small block. now when i get down to business on a race car-different story. i may do some serious investigation into LS power. :seeya:

 

[Case75]

The Comp Magnum roller tip rockers are a resonable price and do provide a good increase in horsepower. The reduced friction helps to keep oil temps down as well which keeps water temp down.

COMP Cams: Magnum Roller Rocker Arms: Chevy; 3/8" Stud, 1.52 Ratio

 

[buckhorn76]

summit has their house brand 1.6 roller tips at 90 bucks for set of 16. they are made by scorpion-good deal. good quality hardened pushrods with formed tips are good insurance too !