283 heads on a 350

[Ziegelsteinfaust]

I got a 350 I disassembled last week to see if it was rebuildable for my dad. So as I was pulling apart I was checking casting numbers.

The block was a last 70's block, and the heads were mid 60's 283 heads.

I did some calculations, and the cr would of been 9 to 9.2 to 1. By my calculus. So I believe the engine was rebuilt this way. As I don't think those pistons were factory replacements. Too much dish in my opinion.

I know from a power perspective it's a dumb idea as they choke the engine up good.

But do they offer any benefits to drivibility or cold starting? Since they have small ports the port velocity would be high. So in theory it could help with drivibility.

Or was the OG builder just being cheap, and using what he had.

[RustyPile]

Who the hell knows what was on the original OG builder's mind.. If the upper valve cover bolts (next to the intake manifold) are closer together than the lower bolts (next to the exhaust ports), they are pre 1960 heads..

Any gain in compression ratio is negated by the small runners.. Another drawback is the heads dont have machined surfaces and tapped holes in the ends for attaching accessories. The combination worked to this point in time, but just OK.. Refurbish everything and put the engine back together. Install the engine and don't look back....

[cadillac_al]

It could have been a big bore sleeper 283 for an old classic car or truck

[Getter-Done]

Are the heads power pack heads?
If so they have the big valves.

How to Identify 283 Power Pack Heads https://carinfohut.com/how-to-identi...er-pack-heads/

[Ziegelsteinfaust]

Originally Posted by cadillac_al

It could have been a big bore sleeper 283 for an old classic car or truck

I measured the stoke. It was 3.48, and the bore was 4 inches.

[Ziegelsteinfaust]

Originally Posted by Getter-Done

Are the heads power pack heads?
If so they have the big valves.

How to Identify 283 Power Pack Heads https://carinfohut.com/how-to-identi...er-pack-heads/

No according to the numbers just standard 283 heads.

[Dead Parrot]

Maybe the builder was short of money, had a pile of parts and needed a very low cost motor to get by.

[AcampoDave]

Some people who run 283's don't even want those heads on a 283. So many better options for a 350 that I'd just leave those stuck in the past. They don't have hardened seats either for unleaded.

[TATE228]

I'm sure someone along the line just needed to get their truck going down the road again.

[Accelo]

The Power Pack 60's 283 heads barely supported the 283 and will be super restrictive a motor that is 67ci larger. The valve stems are not hardened nor are the seats. Only advantage it the small combustion chamber that ups the compression. Like AcampoDave these heads belong in the past. There are so many better options now days I wouldn't waste my time or $ on them. They also lack the bolt holes for modern accessories, it this is a concern. I would install a set of Vortec heads and be done with it.
Cheers

[mattfranklin]

Maybe done for a little better low end torque?
Smaller valves/ports can lead to better turbulence in the combustion chamber.
That, with higher compression might get you a little better fuel economy out of a 350.
Nothing really huge, though.

Like the others guys have said, maybe it's just what he had handy.
One time I helped my brother get his '73 C10 back on the road after a head or head gasket failure (cylinders full of green coolant and it wouldn't start) with a pair of used/rebuilt heads from the classified ads.
We didn't pay attention to part numbers or even valve sizes.
We just knew most small block stuff was interchangeable, so we got them and did a head swap.

We did everything in a weekend and got him back on the road so he could get back to college.

Our main goal was to get him back on the road without thought to much else.

[geezer#99]

Yup! That using what you got backfires sometimes.
My boss had a 73 Impala. Put a ton of miles on it every day doing land surveying. Mostly pipe lines and well sites.
It had a bad rod knock when we got home on the Friday night. His buddy had a rebuilt 283 short block. On the Saturday and Sunday they swapped motors and put the smogger 76cc heads on the 283. It ran but wouldn’t pull the hat off your head. A real dawg. Likely sub 7 to 1 compression ratio.
On several occasions we had to jump out and push start it if parked on a soft shoulder. Even had to get a tractor to pull us out of a field a couple times.
We got to enjoy that for a couple weeks until he traded it off.