Inliners International Forums General Discussion Engines 250 or 292?

Bought a 1972 GMC 1500 with a 250 i-6 and 4 speed. Id like to build a pretty hot six for it. But, I cant decide if i should keep the 250 or start with a 292? It only has 81k miles on it and runs good! What do you think? I know they can use the same cams and intakes but it seems like finding flat top pistons to bump the comression on the 292 can be very pricey! Any advice will be greatly appreciated!

1972 GMC 1500 long bed
No ps/pb, 4 speed, 3.73 gears, 28" tall tires.
mostly street with a few trips to the track every now and then

Not sure if you are wanting to turbocharge it, but it will give you the most power for your dollar. Much much more torque than a naturally aspirated engine.

Maybe look @ this thread.
https://www.inliners.org/ubbthreads/ubbthreads.php?ubb=showflat&Number=67528&fpart=1
Or this one: https://www.inliners.org/ubbthreads/ubbthreads.php?ubb=showflat&Number=62932&fpart=1

MBHD

Actually, the 250 and 292 dont use the same camshaft. The 292 camshaft has notches in it for rod clearance and has the fuel pump lobe in a different location than the 250 camshaft, requiring you to have to use an electric fuel pump if either were installed in the wrong engine.

ALOT CHEAPER TO GO 250

All true above; 250 is cheaper, you can use 307 SBC pistons, etc.
On the 292 you can still get the liquid propane pistons cheap from Sealed Power, they have much less dish and will increase your compression some. I think they cost an extra $90 in an overhaul kit to get them. Flat top your talking specialty and $$$.

Hey there 74f350,

Give Tom Lowe a call, he builds both 250 & 292.
http://www.12bolt.com

For equal or less money that what it would cost to build a 250HP you could swap in a late model GM 4200 Vortec 6 and get either 275 or 290HP with 100% stock reliability.

I had a well built 292 in my truck - got 14 mpg around town 16 on the highway. Swapped in a stock 4200 - mileage jumped to 21 around town and 24 highway with no other changes.

Tom bought the 292 and it eventually was the dyno mule that he did all the 292 dyno work with. After 500+ pulls it was still running strong to give you an idea how well built it was.