How expensive is it to have your LT4 heads ported and polished? how much horsepower will it add? where can you get it done at? would it be cheaper than getting new heads? im thnking about doing this when i put my hotcam in. i would think it would add more power to have P&P heads with a hotcammed engine than with a stock motor. am i wrong?

 

I had a local guy do my heads last week, for the new hot cam. The head work was 350, intake match 75, machine shop 268. Also had new springs 40. The cam and heads are in, having some problems with the rocker arms staying tight. Hopefully will have some seat of the pants results for you by tomorrow.

Max

 

hmmmm, yes please keep me updated.
so you paid 350 dollars to have them port and polish your heads? 75 bucks for them to port match your intake manifold? what was the 268 for? in the machine shop? what that their labor rate? what cam did you go with?

 

I went with the hot cam, extreme duty timing set, off road intake gaskets, replaced my stock lt4 springs with new stock lt4 springs. The machine shop puts the new springs on, resurfaced theheads, 3 angle valve job, new seals, cleaning, ect. The guy who did my heads matched the intakes to the new gaskets and intake, plus matched the exhaust ports to my exhaust gaskets and headers.

 

Also I have heard of people getting 10 to 20% increases in horsepower from porting depending on the quuality of work.

 

See the full story with before and after Dyno tests in my website (link in my signature). I picked up 22 rwhp using the stock LT4 cam.

It cost me just under $500 for pocket porting, 3 angle valve job, back cut the valves, chambers worked, new stem seals, gasket matching, and flow test. I did not pay for full port job since I was not going to change the cam. I did not change the valves or springs as they only had 30,000 miles and were in perfect condition.

My objective was to maximize the flow with the stock cam and after consulting with the shop, it was agreed that it would be a waste of money to do more if I was going to use the stock cam and exhaust system.

You can see from the graphs, torque over the entire RPM range improved especially over 5000 rpm. A friend dyno'd his ZR1 the same day and got 325 rwhp. Then he did a test using NO2, and got 540 rwhp......

 

Youll drop about $1750.00 for a Stage III LT4 CNC porting job and $400.00 for the LT4 intake at CNC Heads (the intake must be done to match the heads). They do really good work (heck, they better for that price) and Pete said some of the LT4 heads they've done are on some of the fastest N/A cars in FL.
Of course, this is marketing/sales talk, so take it for what it's worth... :)

 

Is there some site that explains specific differences between things like Stage 1 & Stage 3 head jobs???? What is appropriate to compliment a hotcam in a primarily street car??? Do the exhaust ports need work if you stay with stock exhaust mainfoold. I am talkng LT4 by the way.

:confused:

 

Just be carefully with local old school speed shop. 5 yrs a go I got screwed with that problem. I go asked around for recommandation for LT1 head porting and polishing. I got people told me oh this shop is highly recommanded bla bla. I spent $1200 for port/polish, intake port mactch and new spring and valve. When I had the combo put together LPE219 shortie header B&B catback open lid 58mmTB and all the goodies. I have the car dyno tuned and only gotten 326rwhp I was pissssed. Every boby I talked to tell me that combo could easily be in the 350rwhp. So the conclusion came down to the head are not flow well.

A couple yrs later. I decided to have Agostino Racing Engine to built a low compression 383ci stroker for the D1SC Procharger I ordered. And I asked Nick to rework my head. BUT I want him to flow the heads before and after. And guess what ?? I find out all the whole truth about what was done to my head previously ported by an old shool shop. The head 220 cfm that is about stock which means I spent the $ for nothing and the spring pressure was 98# is also a wrong seat pressure. You guys don;t how angry I was when I found all this out.
ARE reworked my heads and flow 260cfm and install new spring 130# and 320# . SO just be wared of a local speed shop and cheap labors. I went with a local speed shop before because I was trying to save some $ and I ene up costing more.