Hi guys,

I recently purchased a set of AFR LT4 220 heads to put on my 94 Pontiac Firebird. The motor is a 383 LT1, and the intake manifold is a stock LT1 manifold. I was told that the LT1 intake would bolt just fine to the 220s, however we had difficulty bolting it on. The first bolt-hole on the head and intake would line up, but the others would not.

Then I read on the AFR website that a 3/16" spacer (PN 5607) is recommended between the block and the manifold. Would the lack of this spacer cause the problems I was experiencing where the manifold bolt-holes didnt want to line up with the corresponding holes in heads? My mechanic feels that the intake would have bolted up properly even without the spacer, however I believe that since the bolt-holes in the head are splayed outwards from vertical, that the incorrect vertical positioning of the intake likely caused the misalignment.

Do you guys have any thoughts on this? Would not running a spacer be a possible cause for the misalignment?

Here is the link where AFR mentions the spacer. See item 19 at the bottom of this link:

http://www.airflowresearch.com/support/sbc_install.htm

 

The LT4 heads and LT1 intake manifold are not compatible without machining. You'll need the LT4 manifold for everything to bolt up without problems. Plus on the bottom of that link its probably talking about Gen I SBC heads. Everything there talking about LT1s have a note on there about "LT1 reverse cooled...blah blah". You may have misread it. HTH.

 

Ditto, you cant bolt up a lt1 intake to lt4 heads without lots of machine work.

Best bet is just go go and buy a lt4 intake.

 

I know the ports don't match do to the different runners, but the bolt-pattern and mating surface is the same shape...

The problem is when you try to install an LT4 intake on a set of LT1 heads - now THAT won't work without machining the LT4 intake.

Check out arnie's post in this thread for more details:

http://web.camaross.com/forums/showt...ake+heads+bolt

 

Interesting, I've never seen anything posted to that effect.

Opinion A is arnie could be wrong
Opinion B is something else could be different with the Lt4s from AFR, as oppossed to the "virgin" set arnie was referring too.

 

Yep, definiitely possible. What I am hoping for is someone to post who has run LT4 AFR 220's and encountered a similar problem - needing a spacer due to the intake manifold being lifted off the block by the extra material on the heads. I have also emailed AFR and will see what they have to say.

The strange thing is AFR says that only 220 and 227 heads use a spacer. the LT4 195s and 210s do not.

If I find that the spacer does solve my problem, I will make sure to post about it and let everyone know. I just want someone to tell me it will work before I spend the money on it hehe.