"THEPROJECT" 85 Z28

whats the deal is it one size fits all. Im in the middle of a 305 to 4bolt main 350 conversion and somebody told me that the 305 heads will fit on the new bigger engine block im confused does this work or is my sorce full of crap and if it is possible what does it do for comp ratios im just confused i want to know how this really works
ohh bye the way the 350 is not a tpi its an older one also carberated thankx
also need advice on engine upgrades i believe the 350 is a 78

92RS305#2

most sbc's use the same block as a starting point if the gen block is the same. i know the ones that came in our cars were gen II blocks older than like 70-sumthin were gen Is. the 78 should fall into the gen II category so any head off of like a sb truck/f-bod/vette would work. i'm not positive but i believe this is the case. and you don't want 305 heads for a 350, though it may boost your compression capacity by like half a point your totally killing airflow into the block and loosing volumetric efficiency.

"THEPROJECT" 85 Z28

ive been reading up on the heads and i think that i should maybe go with vortec heads they seem to be quite popular and lots of people are getting great results
also im considering going to a 383 what are the pros and con of the 383

what do you guys think

transambill

A 383 is a good choice but more $ to build than a standard 355 so if your building a good shortblock spend a little more money on a better set of heads.

The Vortec's flow extremelay well for a factory casting and are pretty cheep but have small valves and can only support 445 of lift. Once you spend the $ to upgrade the heads with bigger valves,higher lift springs and machine work you've spent enough to have almost bought a good set of aftermarket aluminum ones.

"THEPROJECT" 85 Z28

A 383 is a good choice but more $ to build than a standard 355 so if your building a good shortblock spend a little more money on a better set of heads.


ok but is the 383 worth the money for the power how much more can i get out of the 383 regaurdless of cash

transambill

Yes it's well worth the extra money over a standard rebuild,why do you think it's so popular. How much power you gain with the 383 as compaired to a stock or even .30 over/355 engine, both haveing the same mods I would think you should see 50-75HP over the 355.(zips up flame suit)
It all depends really. 383's a torque motor and you can get away with running diff. cam profiles as compared to a 355 flat top motor.
And not to get a debate going but torque is what gets you moveing and H.P. keeps you moving.

DarthIROC

any SBC up until the LT1 is a gen I SBC, LT1 is Gen II, and LS1 is Gen III
Any gen I head will fit any gen I block, however not all will necessarily work for any application. a 305 or other non 4.00 bore SBC will not work well with a 2.02 vavle head. Any head before '69 is not going to have all the accessory holes pre drilled. and for 400 applications you need steam holes drilled. If you try to put 283 heads on a 400 you gonna have insane compresion, and the list goes on.

"THEPROJECT" 85 Z28

thankx for all the info about the heads guys that really helped

anthony714

project they right,any heads will fit,but remember if you looking to go up to a 383,why would u want to put 305 heads on???and if you starting from scratch, go 383,cause depending on the material you want,you can get a cast 383 crank for same price as a 350 crank and the rods and pistons wont be any more expensive for a 383.so always go bigger if power is what you want hoss.the 383 build is so common that theres a dump load of crank /rods and pistons everywhere for cheap....if you aint planning on using nos or a s/c you wont need all that fancy forged stuff...so keep it low budget and get a decent head also.thats where your real power will be made is in the heads.and with sbc,theres so many choices for heads that they are cheap also.especially when you factor in possible machine work to clean up you 305s....yuck..and dont look past cast iron heads,they just as good if not better than aluminums for making power.....

Rice Killer87

i bought my hopped up Vortec heads on ebay w/ upgraded springs,screw in studs and guide plates for 600 some odd dollars. bigger valves arent really needed,i have the stock 1.95/1.50 on my car and i would bet money it would run low 13's if it had traction (no posi). thats not bad for only a 600 carb and a very streetable motor combination.

hopped up Vortec's are in summit for 739.90 from GMPP.

not trying to be a wiseass or anything,but ive yet to find any aluminum street head that works as well as the Vortecs do for the price. the Fastburns are close,but are also $1300.00 from GMPP.

"THEPROJECT" 85 Z28

i have a friend that has some heads he will give me brand new already ported vortecs for only 150 dollars this is an insanly good deal i know but what should i do to them once i get them. Like to make them high performance like ricekiller said . What needs to be done

BTW: if i dont wind up getting them you guys can get ahold of me and im pretty sure i can get them to you for 200 no promises but hey its a good deal any ways please continue with suggestions

Thanx Daniel

Rice Killer87

if they done have it done already,you need the get the valve spring seat ground out bigger to accept valve springs for higher lift,have the valve guide hole drilled bigger, especially for a 1.6 rocker arm. install screw in rocker arm studs instead of the stock press in type.

EDIT: you can also get guide plates installed too,that just means you wont have to get self-aligning rocker arms

anthony714

project,have you looked at intakes yet?only reason i ask is vortec heads require different manifolds,and the manifold you want may not come in vortec style.also price out your machine work first..when you start cutting seats and porting,the price adds up real fast.granted the vortec head is a good head,but the newer aftermarket heads are better performance for less after you add in machine work..dart makes good heads for cheap and protoplines are nice pieces also..just do your homework b4 you buy anything.the heads are probably the most important item you can put on