Thanks frscke. It's pretty damn aggravating Hedman says they're for van, and then they don't bolt right on. I'm for sure not running these stock manifolds so I'll post an update when I have one.
1987 G20 1993 Jeep Cherokee 2010 BMW station wagon
ya just have to get the short pipe headers ... even the short headers were questionable with a 454 ...
SUNSHINE VANS-VAN DIEGO ADRENALIN BY THE GALLON & CHASIN RACIN ONE FOR THE DIRT & ONE FOR THE STREETS '93 CHEVY G30 454 4X4 SPORTVAN EXT 146" WB '92 CHEVY G30 454 BEAUVILLE EXT 146" WB
Yeah, I'll get the shortys if the exhaust shop says "no go".
I looked around at shortys today, it's hard to find some that clear the doghouse edge, fit an oval port on a cast iron vortec head and leave the plugs accessible, and are coated. Link that magic part number if you got it
1987 G20 1993 Jeep Cherokee 2010 BMW station wagon
I haven't put them on my "83 yet but I had a set of Doug Thorleys on my '78 with a TH350 tranny...for those having a clearence issue with the Tranny crossmember, I'm thinking there's a difference in the TH350 crossmember and the 700R4 Crossmember in the newer(?) ('83 and up) Vans...food for thought...
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Buddy LeSage
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Yes for the 700R4 you have to cut the collector a little short but there's no reason not to buy the long tubes, any exhaust shop can do it. And shorter headers will definitely have issues with the sides of the engine bay by the floor, and the spark plugs.
1987 G20 1993 Jeep Cherokee 2010 BMW station wagon
Yes for the 700R4 you have to cut the collector a little short but there's no reason not to buy the long tubes, any exhaust shop can do it. And shorter headers will definitely have issues with the sides of the engine bay by the floor, and the spark plugs.
On my 83 with a factory 700r4 I did not have to touch the collector extensions with the older Thorley headers. In fact we extended 2.5" pipe right off the 2.5" extensions for the exhaust. The header collectors had a good inch of clearence under the crossmember. Thorelys are widened out and exit on the outsides of the drop down section of the crossmember. The collector of the thorley itself sits even with the trans crossmember.
Last edited by 1983G20Van; June 29th 2021 12:09 am.
1983 G20 Conversion Van, 350 TPI, Reed Hydraulic Roller cam, Ported 906 Vortec, Edelbrock 3817 TPI-Vortec Base, Doug Thorley Tri-Ys, Dual 2 1/2" exhaust, Speed Density 7730 ECM tuned by ME, 700r4 by ME, Stock 1,600 rpm converter, Rebuilt Stock 10 bolt with posi by ME, 3.08 gears, 358 RWHP @ 5,200, 384 RWTQ @ 3,400, 14.66 @ 95.43 w 2.28s 60'
I put the same headers on my friend's 1984 G20 van with a pypes SGT79S exhaust system and it sounds great, I did have to bend the brake and fuel lines flat against the frame so they wouldn't touch the headers. I can send you pix if you're interested, too hard to post them on this forum