73-87 Chevy _ GMC Trucks > Projects Posts (NOT VEHICLES)

Header fitment

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While I anticipate headers and their installation NEVER being easy... I did not foresee the troubles of the last two days.

My dad came over to help me stick the motor in the hole... it was the most satisfying aspect of 2020... for a couple hours:

Crap... I didnít get the headers in place.

I tried them from the top... no chance.

I tried them from the bottom... way better, but still no cigar.

I pulled the pin out of one motor mount and tried to lift one side for clearance. Still not going.

Dad came back this morning and we got the motor in the hole again... installing the headers after the engine cleared the x-member, but before it settled into the mounts.

Headers contacted... badly... at two spots.

I really didnít want to cut the frame.

But I did:

On the drivers side the cut wound up far enough through the top rail that it HAD to be plated in.

Bottom two pictures are final product, upper two are in progress.

I really didnít want to bash up my headers... but I did:

As I was doing the heating and beating I didnít want to do on the headers I was reminded that the exhaust port location on the AFR heads is raised.

The headers are stainless, long-tube JBA units supposedly for a big block application in this chassis. I cannot say how much the raised exhaust ports play here, but I have trouble imagining these headers wouldíve fit the stock heads.

Definitely not without an amount of swearing and some likely tool throwing.

I canít send them back now.

Hopefully theyíll go in with enough room to install gaskets now.

Otherwise there will be another post from me asking for header recommendations.

3/4 ton with a big block.


Sorry the drivers side pictures are so bad.

I could never figure out why headers fit so poorly.
Back in the day I bought Blackjack alumacoated headers for my 69 camaro.  They were the $89 specials from Summit, so I understand, you get what you pay for.
 On my current 69 camaro I got Hooker super comp coated headers.  I want to say I paid $600 for them (15 years ago), and they still dont fit great.  If it wasn't for the Accell shorty spark plugs it would constantly be burning plug wires.

I had a set of Doug Thorley Tri-Y headers in my 1991 V3500 with the 454 before I pulled it out. They fit perfectly!  I would have sent them to you to try, but now that you have clearanced your frame it seems unnecessary. I have the same issue with the 6.0 l LQ4 in it now...the "conversion" headers don't fit worth a darn. I found 2010 Camaro headers fit great, but the LH side doesn't play nicely with my stock 4L80e shifter linkage. I am probably going to have a custom header made for the LH side. I can't keep buying different headers and hoping they will work.

On a side note, I really wish I had a set of the ICE engine works header making kit!

"I didn't want to...But I did" 2X!!  >:(

I feel your pain Jeremy, can't think of a pair that ever went in perfectly...


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