I've searched and cant find anything. Whats the difference in heads off a roller motor and heads of a flat tappet motor. Also if i use non-self aligning roller rockers on 87-plus head do i have to use a "pushrod girtle"? If so why?

 

A roller block or flat tappet block, in itself, really has nothing to do with how the heads are cast. A roller block or not deals with how the block itself is cast. It just so happens that at the same time there was a cross over for the cylinder heads as well, which is what you are asking.

87-up heads have center bolt valve covers, where the bolts are located in, well, the center basically. Pre-87 heads had perimeter bolt valve covers. Another thing is how the rockers are kept centered to the valves. On pre-87 heads, the pushrod slots cast into the heads are smaller, using pushrod angles to keep the rocker arm centered to the valve. On 87-up castings, the retainer assembly is a bit lower so the tip of the valve extends higher more. Similarly, there is a notch in the rocker arm, where it mates with the valve tip. This notch "cups" the valve tip, centering it to the valve. Because of this, the pushrod slot in the head is bigger, so that it does not interfere with the designed method of rocker centering. Another difference, albeit a slight one, is how the intake bolt holes are drilled. On pre-87 heads, all are drilled at a 90° angle, perpendicular to the intake mounting surface. On 87-up castings, the center 2 bolt holes on either side are drilled at a 72° angle, rather than the rest, which remain 90°.

if you switch 87-up heads over to non-self aligning, you will need some method of centering the rocker to the valve. The most common and highly suggested method is, as you say, by using guide plates. However, by doing that, you also need to have the heads machined for screw in studs as you will need some method then to hold the guide plates in place. That is then done by milling the boss area down and tapping it for screw in studs. Not that there is anything wrong with that. Anything is better than the factory pull outs.

 

I believe self-aligning rockers (I'm sure the lifter statement was a simple brain fade) came in 1988. That makes '87 heads "unique".

 

Indeed the rockers were self aligned. Error on my behalf. Thanks for the catch, five7.

I do remember, I believe it was you, five7, who said he has seen/had some 87 heads that were perimeter bolt, intake angled, and whatnot, but yet were pushrod-aligned?

 

I had an LB9 with center-bolt covers, non-self-aligning rockers.

I've since tossed the heads, so this is all from memory, not something I can go out in the garage and verify.

 

Excellant reply stekman. The reason i am asking if im fixing to start on my HSR 355 in Jan. 05'. Im wanting to do the Vortec HSR but dont know the price for the base and plenum yet, so my other option is i have a "friend" that has these heads (8973498) he wants to sell. But i cant find that casting number. I did though find if i changed my 8's to 3's (3973498) that it pulls up these heads 71'-72'...sbc400...76cc chamber . He said he'll sell the these (if its the right casting number) for $450. They have 8 passes on them since they have been rebuilt. Here are the specs he gave me-----3-angle, 2.02-1.60 valves, seats have been cut and the springs are for a solid lift from .500-.600 lift cam, screw in 7/16? studs, guide plates, and all new seals, retainers, etc. He's also going to give me Harland Sharp stud girdles, comp. magnum RR's, and i think a set of push rods. The block i have but dont want is this (3970014....350...70-76...2 or 4) i have a LB9. I can get the block bored .030, balanced and rebuilt completley for $800. I was going to do that and use a HSR . Would i be better waiting for the Vortec HSR and getting vortec heads, using my LB9 (DIY porting) heads or using the heads stated about.