305/350 cranks and heads (1 Viewer)

[madoc1]

i have a pair of 305 cranks and a 350 block. i always thought that a 305 crank would fit but not work due to the balance weight diff. today i was talking with a local hot rod shop and he says a 305 will work if the #is 442. anyone heard of this?

also 305 heads will work but jumps compression way up?

any knowledge will help thx jim

 

[pbgbottle]

442 is the last digits of the crank # i looked in my book and that was the only crank # for the 305 /350 crank that the book showed

1969-85 3932442 305,350

 

[madoc1]

bottle- that sounds great info. need to tear out the cranks tomorrow. wow , just love this forum!

thx, jim

 

[madoc1]

any idea on the heads? jim

 

[Gumby]

They bolt up, but I have also heard they bump up the compression. I have a set on a 350 in my T100, but it has yet to fire so I don't have any real answer.

The hot setup is 5.7 Vortec heads on a 350. You need a special manifold, but they flow way better than either 350 or 305 heads. they go for about $100 a shot around here.

 

[pbgbottle]

depends on the casting also of the 305 heads they may be what some call the light weight casting . less material in them prone to warping and cracking .also have smaller runners .( don't flow well ) the only gain from the 305 heads would be compression . i too would go for the vortec heads . straight out of the box they will outflow any older cast performance head . (camelhumps etc.) the vortec even out perform some of the aftermarket aluminum heads . so i've read . .

 

[pbgbottle]

pic of light weight head can see metal removed from between the head bolts ,on a heavy cast head the edge of the head would be straight not scalloped
also has larger water jacket holes .

 

[pbgbottle]

heres a pic of a heavy casting head more metal in the casting

 

[madoc1]

305 heads

gumby, et al. i wish i could do a hot set up. but this is a old man budget deal. i guess i will just do it and if i mess up at least the parts are easy to get to. thx all. (if anyone has done this before-350 block,305 crank,305 heads ) might want to let me know.

jim

 

[pbgbottle]

another consideration .is the piston .are you gonna get a dished piston . or use a flatop .and run high compresion .then you usually will have to run a bigger cam . to get it to run .and then lose a almost all your bottom end torque just a thought
.most desriable 305 head is casting # 462624 also has a 58cc chamber , another thing is the 305 head chambers are slightly father apart 21/32 and on the 350 they are only 15/32-inch apart . may be a head gasket issue ? . i did a budget build on my 350 and just traded my 305 and 307 heads to a head rebuilder for a decent set of 350 heads . all rebuilt polished and ported straight up . i wanted my engine to breath .