[Cristianss427]

Hello guys, I'm building a new forged sbc 355, 6" rods for my 72 Chevrolet Vega. I'm looking for aluminum heads with enough flow to pull about 7000rpm with straight plugs. I've seen Brodix Ik 200, and Edelbrock E-210. Also a just saw this heads from another forum http://www.profilerperformance.com/r.../sbc-23-degree

The cam to be used is a Comp Cams XS290S, 3.73 gears and BW T-5 transmission.

Does anybody has an idea of what set of heads is convenient for my engine?, I'm all ears.

Thanks for the help, bye!

[techinspector1]

Your screen name is ss427 and the cam you specified is for a BBC, but in the body of your post, you say you're working on a 355. Would like to verify what you're working on before posting an answer.

Also, since nobody uses a 5-speed to bracket race, particularly not with a 3.73 gear, I have to assume that you intend to build a motor that is set on "kill" for the street. Is that a correct assumption? A cam with the timing of the one you posted will not work with that gear anyway.

[Cristianss427]

Originally Posted by techinspector1

Your screen name is ss427 and the cam you specified is for a BBC, but in the body of your post, you say you're working on a 355. Would like to verify what you're working on before posting an answer.

Also, since nobody uses a 5-speed to bracket race, particularly not with a 3.73 gear, I have to assume that you intend to build a motor that is set on "kill" for the street. Is that a correct assumption? A cam with the timing of the one you posted will not work with that gear anyway.

First of all, the engine is a sbc 355, this is my cam:

COMP Cams CL12-679-5 - COMP Cams Xtreme Energy Cam and Lifter Kits - Overview - SummitRacing.com

The car is not exclusively for bracket race, we also like to use it against Porsches, Vettes, Stangs and some others at a "safe" highway.

I'm curious about the gears, hope you can help us.

[techinspector1]

That cam, coupled with a static compression ratio of 11.00:1, will produce a dynamic compression ratio of 8.58:1, which should be compatible with premium pump gas, particularly with an aluminum head, which leaks off heat faster than cast iron. If I were you, I'd fill out this questionaire and submit it to the experts at Brodix for a recommendation.....
BRODIX Technical Assistance

[F-BIRD'88]

There are many suitable heads with the straight style plug.
Brodix,AFR, Profiler, Edelbrock... etc etc. Keep the cr just under 11:1 for pump gas.

Gears will depend on the car weight,tires size, transmission etc.

He specializes in Profiler heads, among others.
Speier Racing Heads

[hcompton]

Gears should be fine for a five speed since the first gear will usally be too low anyway. Depends on what type of car/truck it came out of. Vega is a small car it should be ok. It will lump. Dont think its not going to be an issue but nothing i could not live with. As a daily driver that cam my be a little hot gears or not. If you spend a lot of time in traffic you may have some issues. Country roads ok. 110 lobe center will smooth it out some.

Th700r4 automatic would be a better choice and faster at the track.

Brodix and edelbrock make great heads. Calling the experts is the way to go. Their heads are a work of art. Got to love em. 210cc will make it come alive with that cam.

[vinniekq2]

If your engine does not rev to 7k with that cam,check for fuel delivery problems. and or weak ignition.gear set depends on use of vehicle not cam specs.

[AutoGear]

I dont care if you start out in second gear or not; a Non World Class T5 2.95 1st gear camaro trans (or the NWC S10 tailhousing and mainshaft conversion) is pretty much on borrowed time with about 350ft lbs. push it to 400ft lbs; and it'll grenade, its anyones guess at how long it survives before it goes boom. I mean you have a light car, but if you launch hard with sticky tires...it's gonna go boom

Get a 2.64 1st gear T10 with an iron case. You can run 3.23s and still have plenty of grunt in 1st, and it'll take the abuse. It'll also shift faster than a T5 and its cheaper to rebuild.

Most T5 parts are either NLA or Tremec has jacked the price up 50-100%; or theres the India/China alternative...

PS we don't discuss 'safe highway' racing here as its a MYTH

[ap72]

Assault Racing Bare SBC Small Block Chevy Aluminum Cylinder Heads Straight Plug 350 383 400 - KMJ Performance

these heads, cleaned up a little and assembled with your valves and springs of choice.

You'll need to mill them some to get to 11:1 with flat top pistons.

At 7,000 RPM I'd be running hollow valves and beehive springs for safety.

[techinspector1]

Originally Posted by AutoGear

Get a 2.64 1st gear T10 with an iron case. You can run 3.23s and still have plenty of grunt in 1st, and it'll take the abuse. It'll also shift faster than a T5 and its cheaper to rebuild.

Your post has given me an opportunity to crunch some numbers, which I love doing. Let's pretend we have a 3.07 rear gear and an iron case T10 with 2.88 first, 1.91 second, 1.33 third and 1.0 fourth.
Final drive in first of 8.84 should provide a good launch ratio.
Final drive in second of 5.86
Final drive in third of 4.08. You could use this as your top gear in town driving and make good use of a lumpy cam.
Final drive in fourth of 3.07 for low r's on the freeway.
Same idea as using a 5-speed or 6-speed overdrive, but using just 4-speeds instead.

[tresi]

Depending on tire or slick size you're not going to pull yourself off a wad of bubble gum unless you have 4.56 to 5.38 gears with that cam and a 4 speed.

[vinniekq2]

tresi 5.38 gears? seriously?
how do you know he drag races?

[tresi]

Who knows what tires he's putting on it. There several 32" tall street tires as well as there much smaller tires. That's why I had such a large range of gears. If you go for the steam roller tires you need more gear. yea, maybe he's not drag racing but what else do you with a big cammed, aluminum head V-8 vega? Drive around town town at 7 mpg going rumpity rump?

[vinniekq2]

tresi,dont forget us road racers out here. 4.56 is a useless gear for me.Not as many vegas running road courses as vettes.I run a much bigger cam than him with 3.50 gears and a heavier car.My car breaks street tires loose 1st and 2nd. I might take my car to the drags next year for fun.2 maybe 3 shifts?