Just picked up a 1960 pontiac 389 I think is stroked to a 414 by Mickey Thompsons shop back in the day, has mt pistons and a stroked crank I think. Big bore motor. Anyone know anything about these engines?
I've never heard of them but I am sure interested in how it was done. The 421 that is slated for my current project could be bigger in the "more is better" line of thought.
Yeah, i'd like to know, too. the 389 can be easily bored to 400cid, and perhaps the remaining 14 inches comes from a minor increase in stroke...but the factory machining on Pontiacs is so good, it may be a standard bore and its all in the stroke...what's it running for connecting rods, the stock rods, SuperDuties, or MT's aluminum rods?
Mickey Thompson sold pistons and stroker kits for many motors of the day. I doubt it was built by him personally.
The guy I got it from has 2 60x50 buildings full of pontiac parts, and about 25 Gtos. I seen the block and he said that it was a 414 ci stroker 389, it was a Mickey Thompson built engine. Mickey himself did not build it but his shop in ca. Did. Each piston has the number of which cylinder it goes in and his full name Mickey Thompson is cast in the bottom of the pistons. I know the man, he wouldn't lie to me, he wasnt even trying to sell the bottom end, I kept asking about it and he said he would sell it. I just wanted to get some info on it. I'll get the stamp numbers off the front. Maybe that will help me.
You sure it's not all bore? I used to have a '59 389 block with .125 oversize Jahns pistons in it, and it figured out to 413 cubic inches.
I think it is bore, the crank is a 3.75 arma steel casting number 531369. The engine code is 158p. I can't find that code anywhere on the internet. Also there are two more sets of numbers, one under that code that reads 80396, then another code more toward the intake area that reads A352185. The pistons like I said have his full name and I know they are 1.-something bore. 1.45 I want to say!?
I'm not trying to sell it, or say its worth a ton of money or anything like that. I just want to know what I have is all. I have a huge collection of MT memorabilia and when I heard the history I thought it would be something cool to add to my collection.
I know of another one of these engines, all done with overbore. I don't think .120 overbore on a 59-60 389 would have any problems, these have very thick cylinder walls. Heck you could also be period correct and go to 523 cubic inches like this engine http://wildaboutcarsonline.com/memb...-_Soup_Swap_Guide_523_Inches_fm_a_389_1-4.pdf
Might the engine code's first digit be an "L" and not a "1"? That would be a 1959 389/260HP. The casting number would be 53200.