hello guys i just bought a set of afr heads 190CC, 2.02 intake, 1.60 exhaust and i want to install them next week. is there something i need to replace when installing this kind of heads on a stock motor? and how much increase in hp should i expect? i have an lt4 hot cam i would be installing later, thanks.

 

A couple of things:

The cam.

The exhaust.

Tuning.Why "later"? I know, turning bolts is LOTS of fun; but, why do it all TWICE? In order to replace the heads, you have to pull the distributor, intake, valve covers, push rods, accessories, drain the coolant, and so on; then put it all back together. Then to change the cam, you have to do ALL that same stuff ALL OVER AGAIN. Why?Heads by themselves, not much; maybe 15-20 HP. Add the cam, another 15-20. Add a decent exhaust starting with getting rod of the manifolds, another 20-25.

Prepare to learn how to program PROMs. Without that, the ECM will continue right along just like it is, thinking it's fueling and sparking a STOCK motor. That's a guaranteed recipe for poor driveability, bad gas mileage, and DRASTICALLY reduced performance from what the parts are capable of. And when I say "program PROMs", I'm not talking about buying a Hypertech chip, or getting some mail-order or over-the-phone tune, no matter who from; those are yet another guaranteed recipe for failure. I'm referring to writing in the new values YOURSELF for fuel and spark that YOUR particular new combo, is going to want.

Better injectors than the Multec crap that's on there, would be smart too. I'd suggest the light-blue Bosch 24 #/hr ones, such as Frod uses; you can buy them CHEEEEEP on eBay used; And I mean CHEAP, like, the last ones I bought a few days agao, I paid $30 a set of 8.

 

yeah i might put the cam at the same time, but i dont know what i need to do all that? can i run 1.6 RR's? new pushrods? lifters? can you help me to select the right parts so i can make the most power out of it. thanks.



___________________________________________________________________________________________
5.7 SBC TPI
LT Hooker Headers
Custom 3.5" exhaust
Ram Air, Accel Module, MSD Wires
125 Zex Kit
Best time 9.36@72mph 1/8mile N/A

 

Yes; in fact, the HOT cam kit as you buy it from GM, comes with some of those (Crane Golds in fact). The reason GM picked those is because they fit under stock valve covers. Not my favorite ones, especially for street use, steel ones from either Comp or Crower are better, because they won't fatigue and randomly unexpectedly suddenly up and break in half, like aluminum ones ALWAYS do sooner or later; but you have to get different VCs to use those. Your call. Make sure the valve springs on your heads are set up for AT LEAST .525" of lift. If they're used, REPLACE THEM; get larger diameter ones than stock, such as Comp 986. Avoid cheap ones, like GM, K-Motion, "Z28" ones, or the ones that come in the HOT cam kit which are garbage and known to be inadequate. Get the retainers and keepers that go with the springs, and set them up to their mfr's recommended installed height.Always a good idea: stock ones are crap.Not necessary.

 

What year is your block?

The Hot Cam is a factory roller type cam. Your user info says '86 and 5.7 - unless you have one of those rare factory '86 5.7's, something's been changed. Even then, it wouldn't be a factory roller block (I don't think - not a lot of information about those cars).

So, need to know more about your block.

 

thanks for the info. well a year ago i had a blown gasket i always thought i had a 5.0 but the guy who fixed it said it was a 5.7 with 305 heads but he told me a had a roller type cam. i was looking for the # to identify the block but couldnt find it...

 

well thats cool, dont forget your head gaskets!

 

look at the back of the engine behind the drivers side head. There will be a long number there. Get it. Post it here.

 

You need new pushrods, period. AFRs all use guideplates and will chew up a set of stock non-hardened pushrods real quick. And if you need to buy sticks you might as well check for optimal pushrod length. As soon as you change heads and rockers you might need different length sticks.

The AFRs will likely be night-and-day better than a set of stock 305 heads, even with no other changes, especially on a 350. However, exhaust and cam in addition to the heads will really wake that thing up bigtime, with proper tuning.

 

how much tuning would i have to make? i dont know nothing about that, i know at least i need bigger size injectors, reprogram the ECM, bump up the fuel pressure? wat else... and how hard is it to burn your own chips? is it affordable?

 

https://www.thirdgen.org/forums/diy-prom/

 

alrite so i got me some comp cams magnum rockers, now i need help to get a good timing chain and pushrods...? im also going to get a new set of arp head bolts wat kit do i need? after that i just need gaskets and that will be all or am i missing something...also should i get a bigger TB like a 58mm? and 24 lb injectors be good enough since i will be sprayin 125hp?? thanks for the help

 

This is critical. There's still no guarantee that you can even install that cam.If this is a 350, no. Unnecessary.

 

the only # i could see was GM57LG is that enough or i need to look harder? the block has some oil on it so im going to spray some degreser see if i can get a better look

 

Not really enough...

That's a newer block at least, 80-up or so. So it might maybe possibly be a roller block.

The main thing is, the HOT cam is a factory roller cam; so it uses the factory roller timing set, with the cam sprocket bolts closer together so that you can't use an older timing set. But that also means it requires the retainer plate, or at least, something of equal thickness; which in turn, requires either a roller block, or some fabrication. You can't just stick that timing set into a pre-roller block otherwise.

If you currently have a flat-tappet cam, you'll also have to get roller tappets to go on that cam; either a complete factory roller setup (lifter, dog-bones, spider) if the block can accept it, or a set of link-bar hyd roller lifters.