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Discussion Starter · #1 ·
I may be able to get a good deal on a set of GT-40P heads and I was told that some longtubes headers will work. Well I dont know exactly what brand of longtubes I have on my car because they were installed when I got them and the previous owner doesnt know either. They have a 1 peice flange and on the stock heads a couple of the spark plugs are very hard to get off because of the headers. What are the chances that my unknown longtubes will be a direct fit with the P heads (with no or little spark plug clearance problems)?
 

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Do the headers appear like they were coated/painted? If so they are MAC. If they are chrome/blued then they are BBK.

Many have said the newer MAC LT's fit the P heads but I am still waiting to find out for sure myself.
 

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sskiller did you have to clearance your pistons, by the way i love
Winchester, going 50, though you gotta watch those tiny signs!
 

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cldelaud- no I didnt have to touch my pistons, but I have a DSS shorblock with Probe Pro Lite flat tops.....they have some pretty big valve reliefs. But even with a stock short block you should have no problems, as the GT40 P's are OEM heads and have smaller valves than a regular GT40 head.

Where are you at in WV? I lived there for years before moving here, I was in the Martinsburg area.
 

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sskiller i am pretty far away, in preston co. 10 miles from md, deep creek lake, wisp etc in Terra Alta WV i am going to post a thread on long tubes that will work on p heads, ccm is too expensive.





86 5.0 sdn,98 SHO ,honda 919
 

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Yea, I've been to Deep Creek lake before, nice country out there.
The winters are a little rough up there though.....

Good luck with the stang, If I get some headers I'll post if they work or not...
 

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Discussion Starter · #7 ·
I had a set of mac headers (shortys) on my other stang and they didnt have a 1 piece flange. SO the longtubes have a 1 piece flange?
 

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I have heard that BOTH the 1-5/8" and 1-3/4" BBK LT's will work, with the use of 90* plug boots.

I'll be going with the 1-3/4" BBK's on my P-headed 347...
 

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My MAC longtubes don't have the one piece flanges. I wish they did....the individual flanges were a PITA to line up after I clearanced the headers around the bellhousing. One tube ended up being warped over an inch out of place. Wouldn't have been a problem with one piece flanges.

-Mike
 

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I hope the MACs work with the GT-40Ps because my new engine has them and I really don't want to buy new headers too. Guess I'll have to try using the 90 deg plug boots.

-Mike
 

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The 90 degree boots work awesome, just get the wires from a chevy, most of them used 90 boots to clear the headers as well. Thats all I did and they work fine. Just gotta figure out how to get the plugs out without having to take my headers off.....
 
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