1978 pontiac 400 build help
bassmstr28
12-19-2010, 09:28 AM
I recently bought a 1978 trans am. Car has 66,000 original miles documented etc. Body is very solid although it has been repainted black. Car was originally white with blue interior. Had a blown tranny so I pulled the engine and trans in one shot. I am going to have it rebuilt as the oil was like sludge and the car was started after sitting for almost nine years and was done with a dry start i believe. There is some metal shine in the bottom of the oil pan so I know it is not good. Connecting rod bearing has some slight scarring. anyways here is the plan.
Rebuilt 400
zero decked
flat topped pistons
connecting rods
xe262 cam
heads are 6x-8's
rebuilt
milled .60
three angle valve job
stock rocker arms setup with new pushrods.
stock intake
quadrojet carb that i am going to send out to have rebuilt and tuned to engine.
headers not sure on brand at this point and 2/1/2" dual exhaust with crossover and possibly flowmasters but these may be a little too loud for me.
1800 stall
with a freshly rebuilt turbo 350 that I already have
maybe a transgo or tci shift kit.
Stock rear is posi with horrible 2.56 gears. I would like to upgrade to a disc rear and change the gearing to 3.73 but that will be a later project.
What I am looking to get is around 350 horse at the rear tires. just want something that is dependable and makes you snap back in your seat and hold on.
so any thoughts on what I should do? I have owned a few firebirds over the years from stock 301's that was a 80 to a nice original 77 with a 400 and a killer 81 that was pushing close to 500 hp on the dyno. I am looking for something in between just to cruise and have a bit of fun.
Rebuilt 400
zero decked
flat topped pistons
connecting rods
xe262 cam
heads are 6x-8's
rebuilt
milled .60
three angle valve job
stock rocker arms setup with new pushrods.
stock intake
quadrojet carb that i am going to send out to have rebuilt and tuned to engine.
headers not sure on brand at this point and 2/1/2" dual exhaust with crossover and possibly flowmasters but these may be a little too loud for me.
1800 stall
with a freshly rebuilt turbo 350 that I already have
maybe a transgo or tci shift kit.
Stock rear is posi with horrible 2.56 gears. I would like to upgrade to a disc rear and change the gearing to 3.73 but that will be a later project.
What I am looking to get is around 350 horse at the rear tires. just want something that is dependable and makes you snap back in your seat and hold on.
so any thoughts on what I should do? I have owned a few firebirds over the years from stock 301's that was a 80 to a nice original 77 with a 400 and a killer 81 that was pushing close to 500 hp on the dyno. I am looking for something in between just to cruise and have a bit of fun.
MrPbody
12-20-2010, 08:54 AM
Your "list" isn't bad. It will get you NEAR your target for power.
A factory intake, circa '67-'72 would help over the extremely heavy EGR version you now have. An aftermarket intake to consider would be the Edelbrock "Performer". The factory intakes perform about as well, but are at least 40 lbs. heavier.
Be certain NEW forged rods are installed. The original cast rods were inadequate when new, and are now over 30 years old. RPM sells a reasonably priced set of 5140s for about $250. Speed Pro pistons are the "best for the money".
The XE262H is our most popular cam for mild builds and stock converters. In at least one case, it "dynoed" 265 RWHP at 5,100 in a pump-gas (89 octane) 406. The car, a '68 Firebird ragtop, went consistent 13.70s in street "trim". Claimed 17 MPG, as well. Your '78 is a bit heavier, but still, a torquey engine package and it would 'move" well.
Get Jim Hand's book "How to Build Max-performance Pontiac V8s" published by SA Designs. This is the only CURRENT study of the ol' Injun available. Aimed specifically at high performance STREET engines, it includes much info about the history and mythology surrounding the Pontiac.
Lots more info available. A little at a time???
Jim
A factory intake, circa '67-'72 would help over the extremely heavy EGR version you now have. An aftermarket intake to consider would be the Edelbrock "Performer". The factory intakes perform about as well, but are at least 40 lbs. heavier.
Be certain NEW forged rods are installed. The original cast rods were inadequate when new, and are now over 30 years old. RPM sells a reasonably priced set of 5140s for about $250. Speed Pro pistons are the "best for the money".
The XE262H is our most popular cam for mild builds and stock converters. In at least one case, it "dynoed" 265 RWHP at 5,100 in a pump-gas (89 octane) 406. The car, a '68 Firebird ragtop, went consistent 13.70s in street "trim". Claimed 17 MPG, as well. Your '78 is a bit heavier, but still, a torquey engine package and it would 'move" well.
Get Jim Hand's book "How to Build Max-performance Pontiac V8s" published by SA Designs. This is the only CURRENT study of the ol' Injun available. Aimed specifically at high performance STREET engines, it includes much info about the history and mythology surrounding the Pontiac.
Lots more info available. A little at a time???
Jim
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