[rambler454]

i got a 283 and heads were separate and i can't find the casting number online anywhere. they say 378450?

[GMCBEAST]

Are you sure they don't say 376450? If they do they are mid/late-70's to early 80's 265/305 heads if I'm not mistaken. Had a set myself and I think mine were off a 265. Small valves and combustion chamber. Try googling 376450 as I'm just going off memory and it's been 10 years at least since I had those heads. Hope this helps.

[F-BIRD'88]

They are low perf 305 heads.
They will run on your 283 but don;t expect much power.

If you want power froma 305 head on a 283 get some #4416 heads
and home port them 1.94x 1.60 valves help too.

Vortec heads work very well on 283's too.
mill .040" off the decks and install with a thin felpro 1094 gasket.

the 450 casting heads will be lame on any motor including 283's.

[F-BIRD'88]

Another nice head to use on a 283 is the L-98 aluminum heads from corvette and camaro 5.7L TPI motors casting number ends in 113.
Also found on the ZZ4 350/355hp crate motor.
Especially good after been ported to increase flow.
58cc chambers 1.94x 1.50 valves. Good flow and power when ported.

[rambler454]

I've heard Vortec heads are bad about cracking? I need to send the engine to a machine shop. anyways any ideas or engine combo's like pistons and such would make a good street engine?

[F-BIRD'88]

Originally Posted by rambler454

I've heard Vortec heads are bad about cracking? I need to send the engine to a machine shop. anyways any ideas or engine combo's like pistons and such would make a good street engine?

Only the junkyard vortecs are likely cracked.
The trucks these came on had a intake gasket cooling
problem that caused the engine to loose coolant and overheat.
That what makes any head crack.

if you go for vortecs buy new castings.
The only vortecs in the junk yard or on evil bay are cracked ones.
The good ones get rebuilt and reused
Buy new and you won't get stung.
The GM bowtie vortecs rock.
The engine quest EQ lightning vortecs are very good too.