Original heads on a 70 350/300hp?

[grayw0lf]

While junk yard diving today, I came across a 69-72 C-20 w/ what looks like the original 4bbl 350. What heads came on our trucks in these years to produce an advertised 300hp? & are they really any good?

Valve sizes?
Combustion chamber cc?

[grayw0lf]

Also, if anyone is in need of older SBC's or B.O.P. big blocks, I found quite a few.

[earlysecond]

What are the head casting numbers. This will make is easier to tell what the valve sizes are and hwo well they are rumored to flow. I am only curious but could likely decode them (as many others are able I am sure)
Brent

[Blazer1970]

There was never a truck 350 engine with 300 hp, gross or net. 255 was the highest gross hp rating for 4bbl 350s, and that was re-stated as 175 net hp for the same engine in '72.

[incoma]

I had 441 heads on my 70 truck. 1.94/1.50 valves. I thought the heads flowed good for stock.

[djracer]

been junkyarding without me I see how you're gonna be!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


Just kidding
Kevin

[grayw0lf]

Hey Kevin,

Man-o-man. I hit about every local yard & found jack squat. Norman Bridge was the best, but still nothing. I think I'm gonna get together a list comprised of all the local junkyards & what they have to offer. I'm sure I missed a few.

I figured you were working today. I played hookie.... but I'm paying for it now. I type this from work, at 11:00pm on a Friday night, w/ no end in sight.

I hit....
Norman Bridge
The one on lower wetumpka road
The one on 231, just N of 14 (man, did they have a bunch of our trucks... well... remains of our trucks. I think the last was parted of every useful piece about 10 years ago!).

[crosby]

I put a '70 350 into my Jeep a few years back. It was rated at 255, and it was a four bolt. I bumped the heads up to 1.96 valves to preserve low end torque, and put a Comp Cams towing/rv cam in it for the same. That motor really pulled hard and strong right through. I've always believed that the power is made in the heads, seems to me all blocks should yield the same results given the same bore, stroke, etc. I would grab that motor if I were you! Good luck!

Crosby

[crosby]

or was that my camaro motor? I did have a 70 SS Camaro, I think that was supposed to be 255 horse. Either way, the old motors really hauled a$$!

[Longhorn4x4]

According to the code on the block from my 1970 Longhorn, the 350 in it was a 295HP version. My Dad bought the truck new, my uncle who was a salesman for Chevrolet for 30 years ordered it for him. Dad had thought about a 402, but knew they were really the same as a 396, and the 396 had a reputation at the time for spinning rod bearings. That's why he ordered the truck with a 350, and he told my uncle he wanted the hottest 350 he could get. We got it in April of 1970.

Funny thing, we also bought a new 69 Impala SS Custom, it was a leftover from the previous year, and was powered by, you guessed it, a 396.

We had HUGE campers at the time. The Man O War we had on that truck slept 5 adults comfortably. Even though the truck is a Longhorn, the camper stuck out 12" from the end of the bed. Dad worked part time for a camper sales company (he was a court officer, not to be confused with a bailiff), and designed a slide out rear bumper that would actually slide out far enough to protect the camper. His design got ripped off, and he only made money from a dozen or so of them.

[Gator70]

I was told a similiar story of my '70 GM K15. The advertised Hp is 255 but it is also supposed to be emmission controlled. The only controls on the motor is the TCS. I have no vapour canister etc. Nothing has been removed except for 34 years of grease. When my Grandad bought the truck in the Fall of '69 he was told that it was a 300Hp engine. Im still in the midst of cleaning off some of the grease to get all of the numbers for the engine. But the date stamp on the front of mine is Aug 27/69. Production date for the truck is 9/69 classified as a '70.