Hi all.
I’m new to the board, but not so new to my '72 GS 350 (bought it in '94). It’s basically stock except for a 2-1/2 manifold-back exhaust and Flowmasters. I’ve been getting the itch to do a mild top end rebuild project and gain some much needed HP. Nothing crazy since it sees light street use only.
One area for improvement I’m considering is targeted porting/polishing of the cast heads. I recently picked up a spare set (casting no. 1243452) which I understand spanned several years. Since they came cheap I’m not afraid to try porting these on my own, once I learn more about how to (and how not to) for the performance improvements I’m looking for.
Before I disassemble and have them cleaned/magged, I’d like to know more about these heads:
1. Their production spanned '72 - '80 from what I’ve read. Are any years of this particular casting code more desirable?
2. How do I know what year these particular ones were produced? Each has “A•5” marked on the top left side as well.
3. How do I know if they are smog-equipped, and if they are, how do I “un-equip” them? ;-)
4. In general, is it worth me working on this particular set, or are there other more desirable (so harder to find) SBB heads that I should be searching for?
I’m not much interested in modifying the heads on my car because a) it’s together/drivable now, b) if I sell the car I’d like to give the next guy the opportunity to restore it, and c) in case I mess up the heads I won’t spoil b) by doing so.
Thanks for your help!
I’m new to the board, but not so new to my '72 GS 350 (bought it in '94). It’s basically stock except for a 2-1/2 manifold-back exhaust and Flowmasters. I’ve been getting the itch to do a mild top end rebuild project and gain some much needed HP. Nothing crazy since it sees light street use only.
One area for improvement I’m considering is targeted porting/polishing of the cast heads. I recently picked up a spare set (casting no. 1243452) which I understand spanned several years. Since they came cheap I’m not afraid to try porting these on my own, once I learn more about how to (and how not to) for the performance improvements I’m looking for.
Before I disassemble and have them cleaned/magged, I’d like to know more about these heads:
1. Their production spanned '72 - '80 from what I’ve read. Are any years of this particular casting code more desirable?
2. How do I know what year these particular ones were produced? Each has “A•5” marked on the top left side as well.
3. How do I know if they are smog-equipped, and if they are, how do I “un-equip” them? ;-)
4. In general, is it worth me working on this particular set, or are there other more desirable (so harder to find) SBB heads that I should be searching for?
I’m not much interested in modifying the heads on my car because a) it’s together/drivable now, b) if I sell the car I’d like to give the next guy the opportunity to restore it, and c) in case I mess up the heads I won’t spoil b) by doing so.
Thanks for your help!