[6426yy]

Why didn't you just buy a different engine that makes more power? Or you could have bought a GM short block and then built it up. That way you wouldn't be pulling apart a complete engine that's ready to go.

Just wondering

[75Chevy]

at the time i didn't have the money because i was in the 9th grade of high school and i purchased that engine as a stock replacement.. now i just graduated and i'm looking to learn more about the internal parts and what a better way to learn is to tear one apart... and i still wouldn't have the money to go buy a block and build it up

[curtis73]

Originally Posted by 75Chevy

thanks guys. can you purchase a set of aftermarket, non-vortec heads that will match nicely to a 230 degree cam that will up the c.r. to 9:5:1 producing somewhere between 350 to 400 hp and still keep the stock gear ratios and keep it streetable? or are vortec heads the way to go...

You could, but you can buy a set of slightly used or rebuilt Vortecs for $350-500. Heck you can get them modified for extra lift brand new for $450 a piece. Anything from the aftermarket that will match them will probably run you closer to $1300 for the pair.

Examples:
Vortec assembled heads, new: $560/pr. 170cc runners, about 235cfm flow
Dart Iron Eagle, new: $1150/pr. 180cc runners, about 222cfm flow
Trick Flow aluminum: $1450/pr. 195cc runners, about 240cfm flow
Edelbrock Performer aluminum: $1200/pr, 170cc runners, about 225cfm flow

All of the above prices are from Summit Racing and the flow numbers are from http://users.erols.com/srweiss/tablehdc.htm#Chevy

For the street you always want to get the flow you need with the smallest possible port. Small ports equal fast flow which makes torque. Big flow makes big hp. Theoretically, if you can design a port of the same volume that increases flow, you can add hp without hurting torque. Its a win-win. That's what you get with the Vortecs. Adequate flow from a small port.

Vortecs won't ever be the top of the heap, but for street performance up to 400 hp, they really can't be beat. All the flow, all the torque, half the price.

[75Chevy]

Thanks for all your help. i'll look into buying a set of vortec heads and modifying them to match the lift with my cam... that seems like the more resonable direction to go. thanks again!

[techinspector1]

Vortec heads with 9.5:1 and a 230/0.480" cam will produce in excess of 400 hp.

[454C10]

I'm assuming your current heads have 76cc combustion chambers and 150 to 160cc intake ports which is typical for old style heads.

so if you install 64cc heads the cr will go up into the low to high 9's depending on what pistons and deck height the engine has. I need to see the pistons and know how far the piston is below the deck to get a better estimate.

Furthermore, bigger intake ports will make it much easier to make the hp you are looking for. 170 or 180cc would work well. I would get dart iron eagles, edelbrock performer, or 180cc AFR (if you can afford them). These heads will make another 50hp over a stock gm head (old style heads) even with a small cam.

I have seen a dyno result with afr heads making 345hp with a tiny 252H compcam (206/206) on a 9.5:1 cr 350.

[coldknock]

Originally Posted by coldknock

I'm bored so here goes.

Any hydraulic flat tappet cam from any reputable manufacturer with specifications as follows........

up to 270 degrees advertised duration int. and exh.
106-112 lobe separation angle
0.460-0.490 lift

You may find a hundred or so cams that fall into this category. My advice would be to stick with an older grind to lessen the need for very stiff springs, and lessen chance of having to deal with valvetrain noise.

Choose your advertising gimmick.


Larry

19 posts later and the end result is the same.


Larry

[F-BIRD'88]

use this Lunati Cam with oem GM Vortec assembled heads pn 12558060
without modification. Install with a felpro #1094 head gasket.

Use a vortec style four barrel intake manifold. Install with felpro #1255 manifold gasket. Requires 16 stock GM self aligning style rocker arms. 87 up sbc application.

sell your 76cc heads to someone who doesn't like going fast.

A 650-750cfm carb and 1-5/8" headers with dual 2.5" exhaust is nice.

Your stock GM crate motor pushrods will work fine.