I have a fairly stout 355 that has old double hump heads. Although this will be part of next winters therapy sessions, what is a good size intake runner to look for? I like the AFR heads but from some of the posts, it seem that 190's would be too large. I have 4:10's, M20 gearing. The motor was built before I bought the car. I was told it has pop-up pistons, 10.5:1. I have to run a 50% mix of race gas to eliminate pinging. With the small 64cc combustion chamber, it also seems to me that I may be higher than 10.5. I'd really like to be able to use pump gas.

not too sure on runner size,but the aluminum heads my take care of that pinging(alum.heads let you run more compression than iron)i was looking at sportsman2's and they're 200cc runners(30 - 70 more hp)so 190's maybe good,check with BillK.(moderator)

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My68Camaro (http://hometown.aol.com/dougs68camaro/index.html)This CamaroNet - the Webring for the 1st Generation Chevrolet Camaro site .


Doug G.
68 Camaro
406 ci.

[This message has been edited by DOUG G (edited 07-04-2000).]

Rick,

You may want to do a seach on this subject. There has been some dicussion on this topic lately. My engine is similar to yours except I have forged flat-tops. The 195's are hard to beat. They flow like gangbusters. The AFR website also has some engine buildups that you may find interesting.

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Click here to see see my car and hear 5-speeds. http://www.geocities.com/casanoc

The 190's will work fine, especially with 4.11's and a M20. Even at low lift, .2-.4, these heads outflow the RPM's. This means air velocity and torque. For comparison, my RPM's dramatically increased low end power on my 383 even though they are 15 to 20 CC's bigger than my stock heads. But with 4.11's you don't need low end. With domed pistons and 64cc heads, if it's a small dome your compression it probabably 11.3-11.5 and a large dome will get you up to 12.5. AFR says the 190's are perfect for street 305 to 350 engines. They say domed pistons might need to be modified to run the 68cc heads. If you have 11.3 now, 68cc will give you 10.75:1 and the 74cc's will give you 10.0:1. Calculations are with .040 head gasket and .020 deck height.

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67 Camaro 410sb 11.63 @117.6
67 Camaro 388 ET-???
website (http://www.geocities.com/lonnie67_1966)

[This message has been edited by Lonnie67 (edited 07-04-2000).]

[This message has been edited by Lonnie67 (edited 07-04-2000).]