I rebuilt a set of heads at my uncles shop (recut the valves, did a 3 angle valve job, resurfaced the head, pressure tested). I also smoothed the ports out and took out some of the casting in the heads. I got LT4 springs for the head and full roller rockers. I got everything installed and tested it. The car felt much smoother and stronger on the top end. What would you guys say that the general gain for the mods done would be?

 

and yes I'm aware porting your own heads is a taboo. dont remind me. assume I didn't mess up and did a decent job.

 

I have read that rockers and springs are good for 10-15 hp.

 

10-15 seems reasonable.

 

i could go with that. not counting the headwork and all.

 

How much did you take out of the head? You said removed some casting...I guess flash so Its not like you did a port job...right?

 

i don't have any numbers, but my seat of the pants dyno went up about 15 hp or so.

 

I wish I had pictures. Basically I matched the intake port to the intake manifold gasket and blended it into the rest of the port. Took out all the rough extra casting, thinned the valve guides a little, went over the whole thing with a 100 grit sand paper roll for even texture. For exhaust I thinned the valve guides a little and made the surface smooth to the touch. I did not take a lot of material out of the exhaust side, just smoothed it basically. For the intake manifold, I just matched it to the gasket so the ports on the head would line up to it. Also at the machine shop I put in a 3 angle valve job.

Fun little project, I probably had about 10-15 hours into porting or w/e on the heads and about 2 on the intake manifold.


For the total cost of the project, I'd say it was about $350ish. I got a good deal on the heads, good deal on the rockers. new LT4 springs and all the head reconditioning was done at my uncles shop for free.

Driving: The car is smoother throughout the powerband. Before when getting on first and second, the car would lose traction briefly around 3500-4000 and 5500. Now when I do a first to second run, I lose traction from about 4000-6000 in first and second doesn't chirp so much as just break traction again.

It's a noticable difference that I can't just point and say "the rockers did this". I'm thinking the other mods definately helped.

 

gasket matching is a no no.

 

I've heard it is and it isn't. Who knows.

 

Why?

 

probably something about a larger intake port having less velocity because its larger. that and..... i dont know.

but ive also heard its a great idea.

 

is that 10-15 hp at the wheels or at the flywheel?

 

Your not going to lose much velocity in that...you lose velocity when people hog out the runners, most of the air in that heads is in the bowl and short turn anyway. The gaskets are pretty close as it is.....I don't see where it would be a problem on a LT1...

Just my unproffesional worthless opinion

 

exactly, now it all just matches up. its not like i took out tons of material. i just made everything smoother than it was.