Right now I have a 454 in my vette that has been worked over a little bit and made 570hp on the engine Dyno and runs pretty strong but as always I want more! The engine has kb hyperpereutectic pistons that have a small dome for the 290 casting chevy heads I was thinking of pulling the motor out new forged pistons and upgrading to a 265 Cnc afr heads while in the motor put arp studs in the rods and arp studs or bolts in the mains (2 bolt) I have a roller valve train with a Straub hydraulic roller cam with .620 lift my heads flow a little over 300 cfms don't remember exactly plus the weight saving going aluminum head

if youre changing pistons put a bigger arm in it, little more head too
heads will help for sure but if youre really wanting more that stroke will do it (combined)!

I really want to change as little as possible $ is tight that's why I only want to change pistons to get me the compression I would loose going from the small chambers to the afrs

I don't know that I would want to go to 600 hp with a 2 bolt main block. If anything I would put a set of alum heads on it and not too big. 265's sound too big to me unless you want to turn a lot of rpm. What rods are in it ?

ive got a couple 588'' bbc's,alum heads,1250 dom carbs,roller cams,,10-1 run on pump gas,,made 750hp,you need these,dyno/break-in time only


and you can buy these cheaper then going thru you motor

This is something I would puts on over the winter and spread the cash flow over a few months even though your offer is tempting just not in the cards

you can't just change out main bolts for studs. you need to have the mains checked and then likely line honed.


weight savings of aluminum heads would be pretty decent. if I remember correctly I think a set of bbc aluminum heads weigh the same as 1 iron head.


most people will say 600 is as far as you want to push a 2 bolt block. but you could have drilled for 4 bolt mains.


you don't mention what kind of rods you have?


I did a quick search and looks like both the 290 heads you have now and the 265 AFRs have 100cc chambers, you could probably just throw a set of heads on, pick up some power, plus weight savings. other than that, everything else you mention well you're basically doing a full engine rebuild. Once you get bigger heads then you are gonna want a bigger cam, yada, yada, yada.


not trying to be an *** here, but how much of that 570 are you actually putting to the pavement? you already mentioned money twice in this thread, and everything you mentioned in your first post is NOT cheap. Your $$$ would probably be better spent on getting that power to the ground.

tight on money, and want to do all that work for a 30hp gain?

I would just learn to be happy with 570 hp and put any money toward traction as stated above.

What kind of tires are you running out back?

Seems like alot of work for a little gain. Have you looked at what it would cost to add a supercharger?

I was trying to simplify the rebuild I know it will need to bring it to machine shop for work and I mentioned the money because I know how these threads go! I thought the afrs had 112cc chambers

i had a big long reply typed out and then it wouldn't let me post so here is a shorter version


you are correct its 110cc i read the wrong line.


You are basically talking about a complete engine rebuild. going to have the block stripped for a line hone. all new gaskets, check all the bearings for wear. then you'll likely want a bigger cam after you get the heads. you haven't said what crank and rods you have now, can they handle any more power?


I saw an old thread where you said ran a 8.0 in the 1/8. you aren't using the power you have at that speed, so have you done anything to improve traction since then?


if you just want a high hp number on paper then yes afr heads are the way to go. if you want to go faster, I would put some $$$ into suspension/drivetrain to make what you have more usable, otherwise you might just make it easier to do burnouts

Seems to me 570 H.P. would surely blow the rear tires out...

It's more about loosing the weight of the cast iron head and maybe a little more hp when I ran the 8.0 it had a 3310 Holley on it no spacer and the hood was right on top of the carb also I was using a borrowed m20 from my dads 66 vette so I didn't want break it it now has a 850 ultra hp and a tko 600

I'm in the midst of a similar build, 427 L71 stroked to 460. I don't have Dyno numbers yet (waiting on Icon -18cc pistons). I'm also using a Straub Hyd. roller (.620/233). I already have the 265 AFR's (didn't weigh them yet, but soon). My 68 rect. port heads weighed 71 Lbs each. I'm in Blaine, MN, we're almost neighbors. I'd like to chat sometime soon about your experience with the TKO.

anytime you want chat about cars I'm in! I go to the anoka car show a lot if I'm not there my old man is and he has a 427 rally red 66 with a tko500

I went with Brodix Race-Rite heads- 294cc intake and 115cc chambers. No hassle with exhaust ports either. Stock location. I did have to grind a bit on the headers to clear the head bolts. Compression works out to 10.5 so it's pump gas day.