Porting, head milling.. Ect.

[91CoupeMike]

The heads I have are 60cc and they say for every .006in milled is -1 cc on the chamber. So If I want 55cc id need to mill .03in off the heads.

They say without milling the stock pushrods will work, would .03in be a big enough change to need shorter pushrods?

With 60cc they say it's 9.5:1 compression. I'm not sure how to calculate compression, but 55cc should get me 10:1, or no? This is a stock bottom end 91 302.

Now for porting, I would like to gasket match to a 1250 intake gasket on the heads and intake. Will this be worth it $ wise? Realistically how much gain would I be looking at? Brodix says to use a fel pro 1487 exhaust gasket, but have heard of others. Any inputs on exhaust gaskets or a gasket math port? I'll also be smoothing the header flanges on the bbk long tubes as well.

The intake is a Holley systemax, and the heads are brodix 5.0 st r.

Heres a link to the head specs:

http://www.brodix.com/heads/st.php

Any reccomendations on where to get good quality work done, and what price range would I be looking at?

Thanks in advance.

[Damnittsteve]

good luck on the racecar trick

[FoxBodyNick]

yes 55cc should get you around 10:1 with the stock pistons. Give or take a few depending on your head gasket thickness.

[majorownage]

Volume at TDC/Volume at BDC=Compression ratio

Get a thinner head gasket and mill the heads. It's hard to predict the compression because the variability in the piston deck clearance. Some are 0.005 above zero deck, some are 0.010 below.

Summit had some 0.038 gaskets from Mr. Gasket. Those are the thinnest without going to copper.

I have no clue on the stock pushrods. I would think you would want stronger ones anyways, as your heads probably have sizable springs. Use a pushrod length checker to find out the ideal length and order accordingly.

Porting? Just a nice multiangle valve job on a Serdi...

[greenbullitt]

it will DRASTICALLY change your geometry, you will need a different pushrod, possibly have to mill the intake too

[91CoupeMike]

it will DRASTICALLY change your geometry, you will need a different pushrod, possibly have to mill the intake too

That shouldn't be a problem. What does doing that geneally cost? Just a range of what you'd expect a shop to charge would be nice. I don't want to get it done just to find out later I got hosed.

[91CoupeMike]

Volume at TDC/Volume at BDC=Compression ratio

Get a thinner head gasket and mill the heads. It's hard to predict the compression because the variability in the piston deck clearance. Some are 0.005 above zero deck, some are 0.010 below.

Summit had some 0.038 gaskets from Mr. Gasket. Those are the thinnest without going to copper.

I have no clue on the stock pushrods. I would think you would want stronger ones anyways, as your heads probably have sizable springs. Use a pushrod length checker to find out the ideal length and order accordingly.

Porting? Just a nice multiangle valve job on a Serdi...

The way I was told, if you're going to bust a part, it's a lot easier to change out a bent pushrod then it is to replace a fucked up rocker arm, valve or spring.

[91CoupeMike]

good luck on the racecar trick

Thanks Steve, it's getting there. It won't be a race car but I want it to run %110 and I want to do it once and be confident in what I did being the best possible route.

Hence, why this is taking so long. I want it to be the best it can possibly be.

[FoxBodyNick]

then get ready to spend on a custom grind cam =)

[majorownage]

The way I was told, if you're going to bust a part, it's a lot easier to change out a bent pushrod then it is to replace a fucked up rocker arm, valve or spring.

If you don't have the right pushrod, you can fuck up the entire valve train. The rocker has to be centered correctly with the correct pushrods or else it will exert a force that is not parallel to the valve neck. It will "push" the valve neck into the guide, and cause all sorts of premature wear.

[Emwun Garand]

I had my 4V heads done by Fox Lake and the work was fantastic.

[Damnittsteve]

Thanks Steve, it's getting there. It won't be a race car but I want it to run %110 and I want to do it once and be confident in what I did being the best possible route.

Hence, why this is taking so long. I want it to be the best it can possibly be.

dont talk to me about taking to long. ive been recently motivated to learn to work on my own shit. it may not run, but i will only have myself to blame.

[91CoupeMike]

If you don't have the right pushrod, you can fuck up the entire valve train. The rocker has to centered correctly with the correct pushrods or else it will exert a force that is not parallel to the valve neck. It will "push" the valve neck into the guide, and cause all sorts of premature wear.

Not saying I won't change them too different lengths, but I won't go hardened if I don't have too. It's a hydraulic can, id use hardened if it were a solid roller.

[91CoupeMike]

dont talk to me about taking to long. ive been recently motivated to learn to work on my own shit. it may not run, but i will only have myself to blame.

I hear ya, I do all of my own work and I hate doing stuff twice. Lol

[majorownage]

dont talk to me about taking to long. ive been recently motivated to learn to work on my own shit. it may not run, but i will only have myself to blame.

Working on your own shit is like a drug. You get a nice dopamine/satisfaction rush.

With a 55cc chamber, zero deck, 8 cc dishes, and a 4.100 0.038 head gasket thickness, the compression hits 9.67:1

I think 10:1 will be pretty damn hard to hit without milling like crazy.