Another one of my notoriously long posts!
Cool car! I had 1 '74, 1 '75, 4 '77's and 3 '78's I think I had a '76 parts car in there too.
The coolest part is your car is a solid top and not T-tops! The car will most likely be alot more solid, which makes it more desirable! The T's usually leaked, which caused the floors and rear deck lid to rust out. Do you have the 160mph speedo and the 8 grand tach? I ask because those are getting very hard to find!
I have to ask you some questions...
Look at your cyl heads, (in between the 2nd and 3rd header tube) there will be a casting number on them (In large numerals) it will say 6x or 4x what do you have?
A little history...
Pontiac motors came from the factory with some cool tricks done to them.. Like ported and polished heads, 3 angle valve jobs, knurled valve guides, pushrod guides, torque to yield rocker nuts, dual valve springs and some of the BIGGEST intake valves ever to hit the market. 2.0625" or 2 1/16" The only motor I know of with bigger valves was the Hemi!
The PMD (Pontiac Motor Division) heads are notorious for cracking in between the valves on the second and third chambers. If you tear the motor down, have the heads Magnafluxed/crack checked. Out of the 15 or 18 400 Poncho's I have built or rebuilt I think I have only seen 2 or 3 sets in perfect condition. Cracked heads came about because PMD didn't use hardened valve seats, instead they lowered the compression (7.6:1) to compensate for the use of unleaded gas. It didn't work! PMD designers didn't really didn't worry about that, because they knew the Pontiac block was on the way out/discontinued. The 79 model year was the last year for the Pontiac based motor. Following year cars (80 and 81) had Oldsmobile 403's and Chevrolet motors. The 81 "Turbo" models were a pathetic 301 (design flop) with a single, small turbo mounted on the right hand bank that wiped out all the exhaust valves in about 20,000miles!
Just as a FYI, all Pontiac motors were the same block, there was no Big or Small block as I have so often heard. It was a difference of bore and stroke so a 455 is the same block as 301!
Dump in a bottle of "Lead Substitute" and keep the R's down around 5500 and she'll be OK for a few years!
If the heads are bad, go with a set of TrickFlow or Edelbrock (NOT RPM) heads.
Now is the time to start restoring these cars! They are pretty easy to find and are pretty cheap in price. They won't be in another 20 years though! When these cars were new, they were the fastest cars Detroit produced! Your 75 would smoke a 75-82 Corvette! "Rockford Files" and "Smokey and the Bandit" really put these cars on the map!
I am pretty familiar with these cars, so if you need some help shoot me a PM! I would love to see some interior pics!
This is a pic of one of my 78 "Bandit Edition" parts cars.
