I havent a clue guys. All this BigBlock stuff is totally new to me. I really need someone to guide me into the right direction.

Are my Stock heads OK? Everything I have read says that MkIV heads on a Gen5 is a nono due to the coolant ports not matching up...

How about this Net lash stuff?? will these rocker arms be able to handle a bigger more "bse" oriented cam?

I am going to a low rpm grunt up to 5000/5500 454 here.

As this motor is now, it has LOADS of grunt at like 1500rpm... BUT as soon as it gets around 2500, it just does not seem to do much. Keep in mind this is all in a 92 GMC moving van... SO maybe that is why. Just does not seem like a good "car" motor to me.
My buddies are telling me to just swap the motor over into my chevelle as is, but I do not think I would be gaining any performance over my warm 350.

Please drop some hints to me, if not explaining in detail what I need to do. Thanks alot in advance!!

Curtis graemlins/thumbsup.gif

i think its the cam that is making it have less pull up on the rpm rather than the heads?

isn`t a 91 block still gen IV? I`m pretty sure it`s a 1 piece rear main seal but I thought they were still gen IV in 91. I could be wrong.

That stock 454 makes more torque than your 350 :D
I'd change the rocker studs over so you can adjust the valve lash and get a bigger cam..leave the rest alone.

There's a set of semi-closed chamber heads that fit Gen 5 & 6 blocks. Very similar to the -290, -215 and -063's. They should do the trick.

No.. it is a GenV.

OK so keep the heads.... put in MkIV rockers and adjusters.

How about new pistons and a bore to increase the compression ratio?

What sort of cam?

Depending if your heads are peanut port heads or not which I don't know if they were used on the a Gen V or not, no more then a CC 260HE to a 268HE hy- cam, a good old Weiand 8005 dual plane intake and a 750 cfm, 3310-2 Holley tuned to your motor and a set of 1.75" four tube, long headers will do you nicely for what I am thinking you want with regards to a "up to 5,000/5,500 rpm, grunt street motor!!

I wouldn't even worry about changing pistons or heads, but would install better springs b/c the stock, lo-po BB springs suck!! And I do figure your heads studs should do fine unless somebody chimes in here and say's different at these two cam levels..

And if you do change springs off your motor, I would go back with a .020" thick, steel shim headgasket set to gain a schosh more CR. which your motor can use anyway..

As always, jmho..

pdq67