rgarcia63

I been reading a few threads with 305 head/350 block combos.
It would be nice to hear from completed projects and how well they run, or don't whatever the case may be. Please state what the car was built for i.e. street/strip etc.

Thanks

87cmroiroc305ho

iTrader: (2)

its been done alot, i was considering using my 350 ho out of an 73 vette and matching them up with my 305 ho ported and polished heads, but didnt. its all about higher compression with a smaller chamber, thats all.

jamon8

iTrader: (3)

my car has 210 comp on all cly.

the only problem I have is higher temps with ac on

I am going to get a three core alum rad and a fan on the condenser to resolve the problem

Blackdog36

iTrader: (3)

I don't think it is a good idea since 305 heads have 3.746" bore while standard 350 bore is 4". A 305 head on 350 block will have a shrouded valve area. Plus 305 heads won't flow as good as 350 along with minimal choices in aftermarket. If you are looking to increase compression, changing gasket thickness and milling heads would work.

jamon8

iTrader: (3)

I deshrouded the valves and my head flow very well with the 1.94 valves

87cmroiroc305ho

iTrader: (2)

the pistons t.d.c. shouldnt go over the block surface anyways.....

fiero377ci

well i used them on a 350 s10 w deshrouded intake valve and 1.94. there ok but rpm limited because they dont flow. on the other hand i think the tpi setup will be the first bottleneck. then these heads will be second

zraffz

I ran 305 heads with 58cc chambers (can't recall the casting numbers or valve sizes) on a carbed 350 with a mild cam, 3.73s locked, T5 and the car saw high 13's... it had absolutely no top end though.

TPI

I run the 081/416 58cc heads on my L98, she has some grunt downlow
which is where I drive her the most. Hasnt seen the track, I built it as
a driver/commuter type with decent go-go power.

Had a few issues in the beginning, but Im happy with them
for the money ive invested.. which was practically nothing
and I got a decent pair of heads on there.

racer7x

iTrader: (1)

I am also looking to do a low $$ build. Have a good stock 350 and good low mile 416 casting 305 heads. Not looking to race just good driver with enough vacuum for brakes and spin tires now and then.
This is where I am at.
Stock dish pistons at .027 down and .039 gasket 58 cc chamber = 9.56 CR and .066 quench. Kind of worried about detonation.
Using stock manifolds and heads are mild clean up in bowls.
Trying to figure out cam.
Maybe 260H 212dur and 440 lift or maybe a split grind like 212/218 and 447/454 lift.

Sonix

iTrader: (1)

I stumbled on this thread by accident. Not running TPI, but a 350 & 305 heads combo. The cam and valvetrain really set your RPM range. I've ported my 416 heads, they are now 64cc chambers, and flow quite well. 1.94/1.50" valves, and a gnarly cam. If I had aftermarket ~195cc heads this engine would REALLY SCREAM, but for now it's just a great midrange engine. 2500-5500RPM is quite strong, but it runs out of breathe after that (hard to say if it's heads, carb fueling, air cleaner, valve springs, etc ).

racer7x

iTrader: (1)

I am running a carb- I guess I posted in the wrong spot but this was the closest 305 head 350 block thread I could find in the search.

I am just looking for some other peoples experience with this combo.
Yes I know the valves are shrouded, will run out of air at top end, the heads don't flow that well, etc. but I am running stock intake and exhaust anyway.

Mainly concerned with knock and best cam choice.

bdizzy85

i am currently building a 350 stock block with ported 416 305 ho heads with a thumpr cam with a 465/479 lift.. needs some honest opinions about this

eseibel67

See post #6, well respected expert says TPI heads work well with roller 350 truck short block:

https://www.thirdgen.org/forums/engi...rod-knock.html

racer7x

iTrader: (1)

I have been running the set up from post #10 and am happy with it. No detonation on 89 pump gas. Went with the 440 lift cam, runs good to 5000 rpm.

Eightyninef

90% of the usage will be below 5000 RPM's, so who cars if it runs out of air at 5500 RPM's.

bdizzy85

Ok so i did the 350 swap with the 305 ho heads casting 416 n used a lunati barebones 280 cam n it runs quite well.. would neone kno hp n tq range

bdizzy85

Sry for got to mention i switched to 24lb injectors with a hypertech chip for a 350