First of all, were the Z28 heads just the -186 casting heads, basically nothing too special, except for maybe bigger stock installed valves on the 302 engine?

Also, I've never seen a small block oval port head. I'm curious if there's a reason to this?

Thanks in advance..

yes the 186 casting heads are the double hump 64CC 2.02 1.60 valves that came on all Z28 302s......

They also came with screw in studs and guide plates

"Also, I've never seen a small block oval port head. I'm curious if there's a reason to this?
"

not enough metal there,,,so they just made them as big as they could with what they had smile.gif

There is a SB oval port head AND it is EXPENSIVE and it is called a "splayed-valve, mini-BB" head! It is strickly a GM over the counter head and goes right along with the SB, SB2.2 head and the SB, Chevy/Buick, 10 degree wedge head!!

All are race only heads AND cost a bunch of money!!

I'm not even sure the "mini-BB" and the "Buick 10 degree head" are even race class sanctioned??? The SB2.2 is..

No, there are no hy-po junk yard SB heads out there like you are asking about...

pdq67

There WAS an oval port SBC. Found an emissions intake in the wrecking yard once, and it had me wondering. Considering how small the ports were, I reckon it had to be off a 262 or 267...

Can you tell anymore about it 67??

Anybody else know what 67 GTO is talking about??

If so, please let us all in on it b/c I have never heard of such a head.. Only what I mentioned earlier..

Even the '56, -306 "closed chamber" SB heads I have have 120 or smaller cc ports and still they are shaped like all the rest except little-bitty buggers..

Interesting to say the least??

pdq67

" They also came with screw in studs and guide plates "

I dont think so.

Originally posted by BillK:
" They also came with screw in studs and guide plates "

I dont think so. Yep, far as I know all 302 Z28's, HP corvette 327's & some 350's came with 202 x 1.6's, screw in studs & guide plates ;)
Heads were 461's, 462's, 186's &492's from memory. Probably some more but those come to mind
The 186's & 492's have accessory holes & the 492 is still available from GM I believe.

Mike,
I must not be old enough ;) I could have sworn that they never came on a production head, only over the counter ?

Only the 2.02 versions had screw in studs and guideplates, the 1.94 versions had press in studs. Never seen an oval port production intake or heads for smallblocks, 262's and 267's had regular rectangular shaped ports.

Found an emissions intake in the wrecking yard once, and it had me wondering. I wonder if it was a crossfire intake. Those 82-84 vette/camaro intakes had very very small ports. Almost round. I know I could nearly plug an intake port with my thumb on an 82 z28 intake. The heads themselves were normal, gm just left them mismatched.

True about the crossfires ports being half sized!! Almost square....

pdq67

according to my book on sbc's 186 came with 202/160's only. doesnt mention guide plates but the ones i bought a few years back (supposedly) had the studs and guideplates ADDED as part of the rebuild.

they were used from 1968 to 1972 and saw service from the factory on 327, 302 and 350 engines. wish i still had mine but they cracked out in the area where they were machined out for hardened seats. resulted in an unplanned water injection engine!

Originally posted by 79943:
according to my book on sbc's 186 came with 202/160's only. doesnt mention guide plates but the ones i bought a few years back (supposedly) had the studs and guideplates ADDED as part of the rebuild.

they were used from 1968 to 1972 and saw service from the factory on 327, 302 and 350 engines. wish i still had mine but they cracked out in the area where they were machined out for hardened seats. resulted in an unplanned water injection engine! =
They came with both 1.940's & 2'02's
The 1.940's had press in studs
All factory 2.02's had screw in studs & guide plates

All factory 2.02's had screw in studs & guide plates Hey Mike, are you referring to this particular casting or does this apply to any factory 2.02 head?