8~SaSc~6

i have a 350 im bout to drop into my trans am and i need to kno if it would be ok if i put the cast iron heads (stock) on the 350 (they are from a 305) either way i have a performer rpm camshaft....so i was wondering if it can do this an be fine for a while. i just wanna make it to the darn strip and kick *** and take name
Steph
LOL

five7kid

iTrader: (14)

I've got it planned permanently.

Of course, they aren't factory heads, but they are 58cc iron heads. 1.94" intake and maybe even 1.60" exhaust along with port/bowl cleanup would aid the outcome.

All you have to watch is your final compression ratio. If the 350 has dished pistons, you're there.

Moving from Carb to a more appropriate forum.

mdricken

Glad I did a search - that is the exact question I had.

I just want a running 350 for the strip with a wild cam and relatively higher compression. Bottom dollar setup.

five7kid - what kind of compression do you have with the 305 heads? Thanks

five7kid

iTrader: (14)

I just found out yesterday that the World 305 chambers (at least the set I have) are actually 64cc. I don't know if all of them are like that, or if they didn't machine mine properly. At any rate, I'm happy with that fact.

I'm using Speedpro hypereutectic .030"-over pistons with 10cc total dish & valve reliefs. The block was decked slightly so the pistons are now .026" down in the hole. I'm using a steel shim gasket that is .020" compressed thickness that adds 4.1cc volume. All that figures to 9.7:1 static CR.

F-BIRD'88

305 heads with their small combustion chamber will work fine for a low buck 350.

They'll work way better if you fully port them and install new larger 1.94 x 1.60" valves.

Here's low buck combo to terrorize the strip with what you've got, for low $$$

rebuild the 350 using flat top pistons ( FM h345np)
{for nitrous use increase the top piston ring gap to .026"/.030"}
thoroughly, completely home port your 305 heads , drill and pin the stud bosses. Have a local machine shop machine for new larger 1.94x 1.60" replacement valves. Have them shorten the tops of the valve guides for new seals and high valve lift. Approx .200" shorter than stock. Have the guides relined if nessessary (k-line).
Get new Crane 99846 valve springs. No machining nessessary

get a NOS "cheater" nitrous kit or simular. use a VICTOR JR intake , port matched to your ported 305 heads.

Install your RPM camshaft slightly over advanced in the motor. {cam offset bushing) (103-105 intake C/L) this will enhance nitrous performance. ( nitrous cam)
(4 to 5 deg)

A better cam would be a Crane #113861 click here mechanical cam again installed more advanced in the motor.

Lock the distributor timing out at 36deg for N/a or 28-30deg for NOS runs.

Champion RV8c spark plugs work well with 305 heads (416) for the strip ( cooler short reach)

Should get you solidly in the 11's with 3.73/4.10's and slicks

{If you install a small fuel cell under the hood you can economically run the motor and nitrous on 110+ octane race gas} {required for over 175hp shots}

F-BIRD'88

Doing up yet another of the infamous $low-buck$ 305 heads with a buddy for his "budget car" sportsman.

He has never ported or modded a cylinder head before.
If he can do it you can too.

F-BIRD'88

pics

F-BIRD'88

Once we're done porting and pinning the studs, its off to the machine shop for new larger 1.94x 1.60" performance valves. The guides on these heads were already cut for teflon seals.

mdricken

When I had my L03 I ported the heads and did a 3 angle valve job. The performcance was significant, but it was a lot of work for what I'm looking for in this 350.

All I'm really after in the 305 heads is the bump in compression. Are 305 heads essentially the same as stock 350 heads, but milled for higher compression? I could live with out porting for now if the compression can be bumped up a few notches.

Thanks.

Mr.Wolf

iTrader: (1)

so which gasket u gonna use the 305 or the 350

F-BIRD'88

"I just want a running 350 for the strip with a wild cam and relatively higher compression. Bottom dollar setup."

The "wild cam" is not going to work and is a waste of your hard earned dollars on a motor with stock smogger heads, 305 or 350.
In stock form, 305 heads flow less air than a 350 head. (the valve is smaller)
Unless you increase the airflow of the heads with porting and larger 350sized valves, you'd be better off with a modest cam. Just because you don't have a lot of $$$'s to sink into it, don't bother trying to change the laws of physics. Airflow is what makes horsepower.
The more radical the setup the more you're going to see the benefit of porting your heads for power.
The porting is esentually free power. All you have to do is get out the die grinder and do it.

305 heads are essentually the same as typical 350smogger heads except the intake valve is smaller and the combustion chambers are smaller. So, your compression ratio will be higher. If you want a significant increase in compression be sure to use the thin .015" factory style steel shim head gaskets. others (typical felpro replacements) are thicker than stock and will compromise your plans..

mdricken

Ok - so I will have to port either way.

But would it be cheaper to
A) have a shop modify the 305 valve seats for bigger valves,
or
B) keep the 350 heads with the larger valves and just have the shop mill the heads down to a good compression value?

Sounds like the milling would be cheaper, no??