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**MikeB** · 04-12-2021, 04:19 AM

Below are some numbers that I found for 1969 truck engines. These were still "gross" numbers back then before the switch to "net".

250 six: 155 hp, 235 lb/ft
350 V8: 255 hp, 355 lb/ft

I think GM is now calling your base Goodwrench 195hp crate engine a "350/265", because it's always been known to make 260-something horsepower with a 4bbl carb and dual exhaust.

Anyway, with a 250 six, you'd be giving up ~100 hp, and more importantly in a truck, ~120 lb/ft torque! So, you just need to know that and be prepared for it. Also, that 250 won't be too happy with a 3.07 axle, especially with the usual 29" tall tires. That means shorter tires or a 3.42-3.73 ring & pinion. And don't plan on taking highway trips with a 3.73!

Sure, that 250 six can make more horsepower with aftermarket components and cylinder head work, but most mods like that actually give up some torque at lower RPMs.

Bottom line, if you're stuck on a six (which I actually think is cool) I'd try to find a 292, which in perfect condition would probably be OK with your 3.07 axle ratio, and make as much torque at a 307 V8.

04-12-2021, 04:19 AM	#8
MikeB Senior Member Join Date: Jul 2000 Location: North Texas Posts: 3,425	Re: 350 to 250 swap i Below are some numbers that I found for 1969 truck engines. These were still "gross" numbers back then before the switch to "net". 250 six: 155 hp, 235 lb/ft 350 V8: 255 hp, 355 lb/ft I think GM is now calling your base Goodwrench 195hp crate engine a "350/265", because it's always been known to make 260-something horsepower with a 4bbl carb and dual exhaust. Anyway, with a 250 six, you'd be giving up ~100 hp, and more importantly in a truck, ~120 lb/ft torque! So, you just need to know that and be prepared for it. Also, that 250 won't be too happy with a 3.07 axle, especially with the usual 29" tall tires. That means shorter tires or a 3.42-3.73 ring & pinion. And don't plan on taking highway trips with a 3.73! Sure, that 250 six can make more horsepower with aftermarket components and cylinder head work, but most mods like that actually give up some torque at lower RPMs. Bottom line, if you're stuck on a six (which I actually think is cool) I'd try to find a 292, which in perfect condition would probably be OK with your 3.07 axle ratio, and make as much torque at a 307 V8. __________________ Mike 1969 C10 LWB -- owned for 34 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. 1982 C10 SWB -- sold 1981 C10 Silverado LWB -- sold, but wish I still had it! 1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 23 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then!