[6x400gmc]

First off, Hi! My name is Britt, and I live in the Houston, Texas area. I've browsed on and off on this site for years, but finally got around to joining and posting. I've been involved with Pontiac's one way or another since I was a kid. We ( read: my dad ) drove and raced Pontiac's on both the dirt and strip back in Louisiana, and I helped build and maintain the power plants. They're great engines, which is why when I bought this truck, the SBC 350 had to go. Maybe I'll turn it into a garden planter or something. This was my fifth "solo" build, and though that went painlessly - I really didn't know what to expect when I went to do the transplant.

This is my write up. Enjoy.
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A few months ago I bought my wife an 82 GMC with what we thought was a 305. The truck came with a 2bbl, and what turned out to be a 145 horse 350. I'm not too big on chevy engines, so I immediately started looking for a Pontiac block to put together. We used to race Pontiacs on the strip and dirt, so I'm intimately familiar with them, inside and out. While looking for an engine, I did manage to swap the dismal 2bbl for a proper 4bbl and Q-Jet.


Long story short I found a 74 Pontiac out of a Firebird, and started the swap today. Here are the pics.



This is the 350 chebby while still in the truck. Its ratty looking.




This is the 400. Its .030 over with 4X's, and an 067 cam. I was running low on funds so I had to go with the cheapie 4 tube Summit headers.



After pulling the 350, I set the engines up side by side. I knew the Pontiac block was physically larger, but I'd never had two blocks together for comparison. The 400 makes that sbc look like a Briggs and Stratton.



This is my Flintstone impression. I didn't get far.



I expected the header installation to go very, very badly - as they do in 2nd Gen. Firebirds. It wasn't quite as bad, I had to install them from the bottom, with the engine elevated about 6 inches off of the mounts. I got all the bolts in, sat the engine in the mounts, and everything cleared. Speaking of mounts, I used the stock Chevy mounts with the Firebird's brackets. It fit like a glove.




As the 400 used the same mounts it wound sitting fore/aft in about the same place. I didn't have a BOP bell housing transmission available, so I bought an adapter plate from TCI for cheap. Its 1/8" steel with dual bolt patterns, and supposedly is rated to 600 ft/lbs of torque. I used the supplied bolts and washers to space out the converter, adjusted the trans mount ( I did not have to move the cross member ), and that was it. I didn't even unbolt the drive shaft. Soon after finishing this off, it started pouring.

Next Day.



After everything dried out, I started fiddling around with wiring, hoses, and such. I had to fabricate/modify the battery tray, and remount it on the left wheel well. The backwards Chevy's have EVERYTHING on the right.

The only real problem I ran into, and is yet unresolved, was the column shift linkage. I managed to bend the rod and clear the headers, but the arm that it connects to ( which connects to the trans ) hits the collector while in drive. That means I cannot shift into 2 or 1. Just P R N D, and then it hits. I'll fix that later, or go with a floor mounted shifter with cable.

http://www.youtube.com/watch?v=LMggCM71q5w

I got her fueled and watered, and around 2pm today I lit her off. Open header, 'cause I don't have the exhaust fabricated as of yet. It ran fine. Link above.



This is the truck. I bought this for a couple thou from a Mexican bodyshop in Pasadena. I call this the "Ghetto" truck because of the paint job, and the wheels that it used to have. ( 295/50's on wire wheels ). I sold those off, and bought these stockers ( minus trim rings and painted RED ) with brand new tires. It also came with a front end off of a 91 Suburban, but it was a total hack job. The headlights didn't work, and it was all attached with wood screws. I'm in the process of converting back to the origional headlight/grill configuration. So its all mix matched color wise, but the body is rust free and straight. I figure I can paint it later.

Well, that's it. I haven't driven it yet, so I can't give you a "seat of the pants" opinion yet. All I've got in the truck is a 10-bolt open rear with 3.23's.

Thanks for reading,




Britt