curious to know WHY my 350 had 416 castings on it and how the hell did it run properly.....and how do they work on my 305 .....i wasnt aware 350 heads would work on 305, and vice versa.....

im a bit confused here lol

i think someone needs to explain how this works and wtf happened here....

 

The only difference between a 305 and 350 is the 350's bigger bore. The 416s are actualy a good choice, they make for a good CR for kinda cheap.

 

oh ok, i wa sunder the impression that the bowl/combustion chamber...whatever you wanna call it, was bigger for 350 engines than the 305....

 

Yes it is. but whats the problem?

common 350 heads are 76cc common 305 heads are 58cc

common 350 valve sizes are 1.94x 1.50 some hi perf ones have 2.02 x1.60's

common 305 heads have 1.84x 1.50 valves

 

the 305 ones are smaller, but thats good. Thats what makes more compression.

 

f-bird, the problem i saw , was 305 heads on a 350, was just wondering how they worked or were the casting #s a mistake and they ARE 350 heads, i didnt know they could be switched around like that

 

A lot of SBC parts swap, between motors. Heads being the biggest.

 

F-Bird 88'............ Im fixing to do my 305 TPI to 350 TPI swap. So your saying i can use the heads off my 305 on my 350? Will 305 heads flow enough for a 350 until porting can be done?

 

In stock form 305 TPI heads (#081) flow (a little) less than 350TPI heads
(#083).

But the engine will run fine.
The combustion chambers are smaller 58cc's vs 64cc
so the compression ratio will be higher if you use them on a 350.

You can build-up your 305 tpi heads to be better than
stock 350tpi heads by porting them and installing larger 350sized valves.
Once you've layed back the chamber walls (unshrouding) for the
new larger 350valves the finished chamber size will be right about 61/62cc's
Just right.

 

I thought you said they were lb9 heads?!? a 416 is a lg4 head. The 1984 parts car I have has a lg4 with 416 castings on it.

I thought you said you had a set of lb9 heads?

The bowls are smaller but the head gasket will still seal it so it doesnt matter.

 

i was told 416's were lb9s.....so they are now lg4?? heh

also was told that the 416 casting were the best to work with due to them flowing well to begin with or whatever, is this incorrect also?

 

For a few years 416s were used on both LG4s and LB9s. (And L69s for that matter; some 305s received 601 castings, as well). The first year the LB9 came out was 1985 and they kept the 1955 bolt pattern until 1986. Then for 1987 they switched the bolt design for the manifold and valve covers and had to create a new casting, the 081s.

416 castings are virtually identical to L98 head castings, the 083s. The main difference being the combustion chamber size and the intake valve size, the intake bolt hole angles and valve cover bolt holes positioning. So you already have an advantage by going with the 416s, all you need to do is enlarge the intake from 1.82 to 1.92 and then port and polish them. To replace 083s you should actually use the 081 castings, which are the new style bolt pattern equivelents of the 416s for post-1986 305s. They can ALL be made to flow like Vortecs

 

should i give away my identity and tell you who i am...and risk being banned again?? naaahhhh but ill give you a hint, im someone who was very stubborn about porting and polishing my 416s, then finally did it....with a 2 hp 5 gallon compressor......