Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
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what would happen? i know the chamber size is 58cc....wouldnt that just add compression or is there any reasons it would run bad? i know the zz4 crate motor has 58cc chamber heads on it and it runs 10:1...id like to build the 305 up for now because i really dont think ill have the money for AWHILE to do a 350 swap
__________________ 1988 Camaro Sports Coupe
350ci, 9.6:1 compression, l98 cam, lo5 heads, holley street dominator intake, holley 670cfm street avenger, hedman longtube headers, true 2.5'' dual exhaust, 2 2 chamber flowmaster mufflers exiting through turndowns.
I got a 3'' hooker catback for xmas
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Do to the smaller size bore of the 305, the valves will be smaller then those designed for a 350 head, which would limit flow.
__________________ -Justin- out of my mind and I'll never know why '86 Pontiac Firebird 305-4bbl / 700R4 T-Top WS6
'92 Pontiac Firebird 305-TBI / 700R4 T-Top
'76 Chevrolet Silverado C10 350-4bbl / TH350 longbed click for my Homepage at CarDomain to see my mods da computer: AMD A64 3400+ @ 2.6GHz in green Aspire SuperAlien case.click for a pic! Teddy!
The major advantage is what you've already said, the comp. ratio.
The other is that since the chambers are smaller, that's less area that the walls in the chamber are gonna have to shroud the valves. And since they are 1.94/1.50 valves instead of the 2.02/1.60 valves in the 350, that will also decrease shrouding. Shrouding becomes a problem when you use big valves. And really, 2.02/1.60 valves aren't really needed for a street/strip car if the car spends more than 90% of it's time on the street.
And the S/R 305 Torquers are the exact same heads as the ones for the 350, just smaller valves and chambers. So you aren't lossing any runner volume at all.
If you are swapping heads, you can check the ccs of the valve relieves on the pistons. From that you can choose a gasket that will give you the proper compression. Lower the better, especially if you dont know the specs on the piston. 10:1 is safe.
__________________ Colin Finkle
'87 Camaro SC
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only thing that sucks about having the high compression is i couldnt run power adders like n2o unless it was built...the zz4 crate motor with 58cc heads made 10:1...the pistons are more than likely gonna be l98s because i found the entire rotating assembly for 1100$...sounds about my range...how much power would i pick up from switching the heads and everything over to a 350...?? i mean roughly? how much does that 45cubes really help...i was thinking i could probably run juice on the 305 to make up for that
At the risk of continuing to kick a dead horse, I'd like to clarify a few things said above.
True, the WP S/R Torquer 305's have 58cc chambers and 1.94/1.50 valves, same as ZZ4 heads. But, the ZZ4 are aluminum, which means you need more compression to get the same power - that's why they do that. 10:1 aluminum and 10:1 iron on a 350 are not the same, so don't assume ZZ4-like performance with the WP 305 heads on a 350. And, the chamber shape is differnt between the two heads.
Also, the Torquer 305's are closer to the WP S/R design for 4" bore engines than to the S/R Torquers, with a smaller chamber for the 305. So, they aren't quite as good as are the S/R Torquers that are intended for a 350, on a 350.
Finally, if you put the S/R Torquer 305's on a 350, you should use at a minimum a thick head gasket, and probably dished pistons as well. The shrouding of the valve will now take place at the chamber wall rather than the cylinder wall, so a little work at that point will help the 350 breathe a little better and also increase the chamber volume slightly.
Assuming you're making 1 HP/CID on a 305, you'll likely gain more than 45-50 HP putting the same things on a 350. The 4" bore is really that much better than the 3.736" bore of the 305 with the 1st gen style SBC heads. I have thought about doing the same thing (putting my heads on a 350 shortblock should I want more than my 305 will deliver), and the L31 shortblock is what I was considering (dished pistons, which produce 9:1 with 64cc heads, and I'd open the chambers up a little around the valves to unshroud and increase the volume to about 60cc).
i might just go ahead and put 350 heads and intake on it...maybe the vortec...so ill loose a bunch of compression i dont plan on keeping the 305 for to much longer...just helped a buddy of mine put a 9psi paxton supercharger on his mustang...now id like to get a blower
I'd say plan for your final configuration. Whether to bother putting some of the stuff on the 305 first is up to you. I probably wouldn't, although I did put my intake on before the rest of the mods to the LG4 (was getting antifreeze leaks on the original manifold, so it was coming off anyway).
Teddy! 
Shrouding becomes a problem when you use big valves. And really, 2.02/1.60 valves aren't really needed for a street/strip car if the car spends more than 90% of it's time on the street.
