So my friend gave me a pair of 862 heads for free! I'm planning on sending them to Texas speed for the port and valve job. I have a 1999 Trans Am ls1 A4, slp lid, chris1313 ram air, mild cam (218/227 .600/.600 valve lift 112+2 LSA), LS1 intake, 1 3/4 long tubes contacted to a 3" y pipe. Car put down 376rwhp. What would I expect to see when I put these 862 head on?

 

These will raise your compression ratio, so a slight power gain will be expected from that alone. With the porting job and the possibility for slightly larger valves, they will knock your 853's or 241's out of the park! You'll want to ensure to install valve springs that can handle the .600 lift from your cam.

 

With the porting and locating an LS6 intake you should see 410-415

 

I've seen reports of around 40 hp or so. For the money you'll be paying all said and done, you are getting one hell of a bang for the buck lol

 

Kinda makes a guy wonder if the quest for 243/799's is worth it? Especially when once ported, the truck heads do nearly as well! And by nearly I mean close enough!

 

I remember TSP saying their stage 2.5 LS6 heads were worth about 8-10 hp over their stage 2.5 5.3 heads. Now that was at peak power as well. The PRC 5.3 head might have a 8-10 hp advantage down low and midrange. Either way the heads are very close when done by the same company to keep it a fair comparison

 

The CNC program likely removes a bit more material from the truck heads to make them "more equal" to the LS6 head. As said, there are still some differences, but not enough to turn down a nice CHEEEP set of truck heads! lol

 

I like what im hearing I got the heads completely free. And I already have PAC racing 1218 valve springs in my current heads on the car so I'll just swap them over so the 5.3 heads when I get them back.

 

Free is SO good! lol Lets you justify putting money into them to get their full potential.
I'm assuming they're getting the Stage 2.5 porting job. This way you'll have nice-size valves and pretty decent ports. You are well on your way, my friend!

 

 

That is a GOOD question! If the heads are milled, you should measure for pushrod length as the vertical height is changed. The top of the head will be closer to the deck, to put it simply. When building an engine it is just good sense to measure anyway. Head gasket thickness could be different, etc.

 

I think it's gonna be extremely close on the push rod length. Ask TSP on that one

 

 

Well there ya go. Might as well make sure they're right!

 

 

Also just wanted to know it looks like the head itself has some scratches on it not really that deep but wanted to know if they'll still be okay. Can also see the one exhaust valve doesn't look the best but I'll be changing valves.

 

On the pushrods, if once you check the length and you need the same length as the present ones, check them for straightness. If ALL are PERFECTLY straight, you might get away with using them again. Your call. I think I would get new, stronger ones.

 

 

Whoever works them over should take off a thousandth or two in the cleaning process. Should remove those scratches if they're not too deep.

 

So this is a good route to go then? Texas speed charges 1000 for everything (stage 2.5) got the heads free. 1700 for ported 243's I think I'd save the 700 for this lol