Thread: how feasable is it

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So heres my problem i have never tried doing this so bare with me the question seems out of wack!!!

can i take a set of stock 350 heads and bolt them to a 305 small block on propane without the worry of the valves smacking into the cylinders and blowing everything out? i know it might sound strange but i have neve tried these things out cause i typically have an engine tore down with the parts sitting right there for the application im am working on you 454 or 350 usaully just the parts rebuilt that came off the project..

thanks for all your input in advance guys..

I dont think you can the 350 has a larger bore then the 305 I tried to mix mach once 350 heads and a 350 crank and was told ya couldnt used the heads but I aso found out later the motor ran real good un till 2000 mile ended up breaking the crank in two places something about the rod are balanced diffrent

Originally posted by techinspector1
The 350 head will bolt to the 305 block, but you'd be going in the wrong direction. Propane is a high octane fuel and will support a much higher compression ratio than gasoline will. Depending on what the 350 head came off of, the chambers could be anywhere from 64 to 76 cc's. The 305 heads were 58 to 60 cc's, so you'd be lowering c.r. when you should be raising it. Although remote, there is a possibility of mechanical interference between the intake valve and the edge of the bore. Even if there is no mechanical interference, there will most certainly be a mixture flow problem as the mixture hits the ledge formed by the block deck because of the smaller bore as the mixture finds its way past the valve. I can see this combination working the other way, a 350 block with 305 heads to raise c.r. and take advantage of propane's higher octane rating.

Here's an interesting link to the new Ford head that Jon Kaase developed. It substantiates the importance of keeping the intake valve away from the cylinder wall.
http://www.jonkaaseracingengines.com...d_s_new_s.html

thanks techinspector1 I realy need to learn something today thats some good info

chevythunder sorry about that I did not read your post right I must be stuck on stupid to day or somthing