Looking for motor options

Asked by GuruF1L3C Apr 26, 2020 at 12:36 PM

Question type: General

I have a 72 Pontiac Grand Prix with a 400 motor
and 400 trans I think I may need a head gasket
however I've been told I could possibly have a
cracked head or cracked block if I have a cracked
block my motor is no good I have been looking into
crate motors but to find a Pontiac 400 other than a
high performance motor is just impossible I don't
the car is not at the point to where I would want to
put 8 to $10,000 maybe even more into a motor I
have seen 350 crate motors for about 3000 give or
take my question is would the three with a 350
wheel bolt up to the 400 transmission and would I
be able to make that work in this car

2 Answers

155,845

If you're experiencing overheating, and you've tried everything you can think of and it continues to overheat, check the timing chain. GMs of this time period used a nylon (plastic) camshaft sprocket that will eventually wear, crack, and fall apart. The timing chain will get sloppy and jump. This causes overheating, lack of power, and late transmission shifting. Check your ignition timing with a timing light. If the ignition timing is retarded (late) the timing chain is the culprit! Hope that helps! Jim

If the block is cracked you would probably have a major coolant leak. Heads can be tested for cracks and replaced if needed and the cost is not all that high.

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