I'm building a 350 next summer and was wanting to do it as cheaply as possible and still have a killer engine. Would 305 heads work on a 350? I'm aiming for pretty high compression(around 12:1). I'll be using 350 pistons obviously that are designed for heads with 64cc chambers as opposed to the 58cc chambers on my heads. What kind of pistons should I buy to get the compression I'm aiming for? Domed or flat-top?

Sorry, that was a bit convoluted.

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1986 Camaro
Carbureted 305
700R4

 

Yah they'll work, but you'll also choke off the airflow that the 350 engine needs, so any gain from the higher compression, you will lose with the choked off air thru the 305 heads.

Remember, Speed costs money.

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1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

ON the same note kinda, where and how much can I send some 58CC world products torquers to get 2.02 intakes and 1.6 exhaust valves along with a fully ported and polished job. Would these flow over 240cfms? I think they flow arouund 200-210 stock. (Intake)

 

305 heads on a 350 is a bad idea, like kevin said they'll choke the air flow. as for pistons flat tops would be better as a rule because they wouldn't interfer with the flame front as it travels across the piston, but it'd be had to get the compression you're looking for with flat tops. i'd look at lunati,ross, or C&A for my pistons. seems funny to be wanting 12:1 compression and all the extra work, problems, and expense that goes with it and then try to save a few dollars on heads. you'd be ahead do go cheap on pistons and spend the extra on heads,cam, and intake.

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ICON Motorsports
1st & 3rd

 

I would agree with the others, but I must ask ... Why do you want to build such a beast (12:1, cheap 305 heads, etc ...)? Are you going to run a budget claimer racing class? Because for street, we can offer different combos, that would not require race gas to run, but rather 87 octane. Yet still be potent enough to kill that 305 headed, cheap 350 you plan on. If you want cheap heads, go with OEM 64cc, those will be better on a 350 than any seriously built 305 heads. The only way I would even consider running 305 heads on a 350 would be for a very low rpm (upto 4500 MAX rpms), torque orientated truck. But only if I had the heads and the short block was very cheaply built (read as OEM stuff, nothing special). And it would require no additional money or machine work to complete.

As for getting larger valves on the 305 TQs, any machine shop can assist with that (I believe we discussed how to look for a decent machine shop in recent threads).

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George P. Lara
Z28s Owned:
1984 "L69" A4
1994 LT1 M6
Member: SCCA, SCFB, SC3GFB
Camaro Info: MadMike's

 

...I had a guy email me once about my ported 305 heads. He had something like 80 hours into his 305 heads, and was able to get them to flow nearly 190 cfm on the intake, with a 75% I/E flow ratio.

There's your quantitative data. You can make them flow about as good as a stock set of old camelback heads, but you'll pour a ****load of money and time into them to do it.

Still, my 305 heads on my 305 are helping me do 101 MPH.... they can't be THAT bad, can they??



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Daniel Burk
http://www.isthq.com/~dan/fcar.html
'84 Trans Am WS6/L69
KB SFC, Moser axles, Torsen Diff. PST suspension, Braided stainless brake lines, Koni struts, 11-inch rear disks,Spohn Adj. torque arm,
Ported 305 heads w/1.94"intake valves, Comp Cams XE262H, Griffen alum. radiator,
Turbine Technologies 2500 stall converter, underdrive pulleys, Crane Hi-6 & more.
1.05g skidpad verified.
New best E/T! 14.039 at 100.82 MPH in 41 degree air at Stanton, Michigan.

 

No, they're fine for a 305, but not on a 350. Dont forget the bore size is different too. The 305 is 3.73" or something like that, and the 350 is 4". Plus the 305 uses 1.84" intake valves and the 350 uses 1.94" intake valves.