Vortec 305 Heads On A Vortec 350

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11-09-2006, 07:57 AM
Itoldyouso

Vortec 305 Heads On A Vortec 350

I bet this question has been asked and answered a bunch of times on here, but I did a search and couldn't find any. I'm not good with computers, so that could be the reason. :o :o

I have my 350 Vortec engine I am going to build for my T, and was going to use the 350 heads that came with it, however, I have just been given a brand new set of 5.0 Vortec heads free, so I would like to use these for obvious reasons.

I called my machine shop guy, and he says they will work fine, and that it is done frequently to raise compression, but he didn't know how much it will raise it. I also understand there are two versions of the 5.0 heads, one with a 1.8 something valve, and one with a 1.9 something valve. Mine is 1.8 something.

Not looking for high flow or performance, just a good running/ dependable engine, so I have two questions:

1) How high will the compression ratio go with the 5.0 heads? (I don't mind running hi test)

2) Do all the stock pushrods and all from the 350 roller work?

Thanks, and sorry if this has been hashed out before.

Don
11-09-2006, 08:04 AM
madgrinder

Valvetrain components should interchange.

Compression also depends on piston design, deck height, head gaskets, and top-ring height.

Higher compression does not necessarily increase power... if timing advance has to suffer to keep it from pinging, so will performance. I would rather have a lower compression engine with a very good timing curve. It will be more responsive and last longer.**)
11-09-2006, 10:05 AM
shawnlee28

Those heads are either 56 or 58 cc.With the old head ccs you could determine how much of a increase you would get,...ie 1/2 point 2 points more.If the numbers are on the block front pad ,block is not milled ,That leaves the pistons.025 approx down in the hole . You could peek in the sparkplug hole and see what type pistons,d-cup,flat top or big dish and get an approxamate static compression,need cam specs for dynamic compression.Could end up with pretty good gas mileage with those heads too:D I could see 1200 rpm at 65 cruse with that set-up. My mustang at 65 is at 1500 rpm and thats a 302 , plus more vehichle weight.