i found the thread with this pics, but they have been removed... trying to help a buddy of mine convince an engine shop that sbc heads and lt1 heads are NOT the same and that those guideplates wont work because they put one of every cylinders rocker arms halfway off the tip of the valve.

 

If you have to convince an engine shop something like that, it's time for a new engine shop. Not to mention, all your buddy has to do is say "I want to use these guideplates" and the shop should oblige.

It should only take 5 minutes for them to realize the alignment will be off. Let them bolt one on and see what happens.

 

If they set a SBC guideplate on the motor drop in pushrods and rockers and think that alignment is OK then I would worry a whole lot about the rest of their work.

I CAN understand a shop being skeptical of so kid off the street saying he read something off the internet. Show them, if they think it is fine then be scared about the rest of the work. If they see the trouble then great.


You have to understand what shop have to deal with. One time I was in the parts store and a kid wanted a "blowoff valve", as I watched the counter guy try and help him we came to realize he wanted a cone air filter. Imagine the laughter after that kid left. IMO this sort of thing is common so for the shop to trust your friend he will have to somehow establish credibility.

 

Ive never had an issue with sbc guidplates.

 

Depends on which guideplates. Tried the Comps once and the fit was terrible, GMPP ones fit OK but still got warn badly, Isky adjustables were my end solution.

 

Not all cylinders exhibited the same amount of skew, but I found the GM 14011051 plates centered better than the SBC.

 

A LT1 head is nothing more than a traditional D-port SBC head with passages for reverse cooling. All dimensions are the same. Valvetrain geometry has a lot to do how a rocker sits on the valve tip. Not all setups have the same problems as some encounter with offset rockers.

 

I has heard in the past that all dimensions were not the same. IDK, but I can't see why SBC plates seem to work on every SBC head, but don't seem to on every LT1 head. Makes you wonder...

 

I have heard the story both ways.

One of you knuckleheads I am sure has some LT1 and SBC heads probably sitting on the kitchen table. How about a quick check?

 

I did it years ago and posted pic...laid a trick flow right on top of a comp...all were the same. GMPP ones too.....

 

Not exactley true... Lt1's have a wider valve spacing.. I would get some trickflow or gmmp guide plates.. Call a well known lt1 cylinder head guy and get his opion...

 

I think he was talking about measuring heads, not guideplates. But my GMPP plates were definitely different from the SBC ones I had.

 

well again, i really want the pics of the damaged posted by the guy showing the messed up valvetrain. iirc every cylinder had the one offset rocker arm / rod combo and it had ate a notch into the guideplate.

he also posted pics of like a diagram or something out of a tech book or something showing that the lt1 valve spacing was like 1mm wider.

 

I had a set of Comp guideplates setting around and i laid them on the guideplates that came on my afr heads, and it was quite a bit of difference with the naked eye!! The valve spacing on my AFR heads is the same as the stock heads i have.

One thing i noticed also is i have a set of old SBC factory iron 041 heads with 2.02/1.60 valves and comparing them to the AFR heads the valves in the chamber are closer together on the old iron SBC heads.the difference is in the milimeters.

 

I compared the GMPP ones to Comp and they definitely were different, like you could measure it with a tape measurer, no calipers necessary.