I've been looking for a donor engine for my 68' Firebird and came across a 69 Grand Prix SJ with the origional engine. From what I've seen this 428 engine had some pretty impressive HP and Torque numbers from the factory. The engine appears to be all intact and the owner says it ran when it was parked. "They probably all do." Anyways he won't sell the engine seperate and wants $2500 for it. Any opinions why I should or shouldn't buy it. I have no use for the Grand Prix body. My bird has a Pontiac 350 in it and I am wanting something that would be very fun to drive. Thanks for any opinions anyone gives.
If all you are after is the engine, I would not pay that much. For the 2500. you could put toward a re-man or aftermarket engine and be farther ahead unless you like sitting on parts cars. I recently picked up a running '70 455 for 500.00.
I had a 69 gp sj with 428 and it had huge power. I would never pay 2500 for it though unless you could swap out engines and get your money back for reselling the car.
Thats just it. From what I've seen doing some research on the internet the 428 put out 370 Hp and something like 440 Ft/Lb of torque. Those are nice numbers but the condition of the donor Grand Prix would be very difficult to get rid of let alone sell.
The guy I bought the car from said the engine came out of a 1970 Firebird but the numbers I have found on it I believe say different. The engine has YM on it and I believe the code by the distributor says DN73. The heads have 46 stamped on them. It came with a 4 bl carb but it and the intake manifold are after market.
"YM" is either a 350 or a 400, and neither from 1970. The block's casting number is right behind the passenger head. There is a casting date code on the block next to it - toward the distributor. Those two items, along with the block code YM will tell what motor it is. Either way, YM doesn't sound like a 428 at all.
""The guy I bought the car from said the engine came out of a 1970 Firebird..."" It could have , it was just that someone else swapped it some time before...lol w/ "used cars" like these , lots of people think thats whats on the car is original, but very often they have been 'worked over' before... Unless you can verify w previous owners....I would not take anything as 'the truth'...
