Fast355

iTrader: (2)

I am building my 305 back up to replace the 355 with the broken crank.

The 355 is to become a 383.

Here is my thoughts, I am thinking of using the 193s from the 355 on the 312. 9.02:1 compression is what I calculated with a composite gasket or 9.13:1 with a steel shim.

On the last 305 I built with these heads I used the composite gaskets meant for a 350. Am I right or should I use the 305 gaskets. I was thinking that the 305 gaskets would get in the way of the bore? I don't want to mess this build up as the heads are hard as hell to pull once the engine is in. On the RS I wasn't worried about it but on the G20 I am.

I am keeping the stock TBI intake and my Ultimate TBI moded front pull TBI. I am just switching to a 91 305 caprice calibration and going from there. Oh and 65 lb/hr caprice injectors.

Oh and the cam is a Comp Xtreme Energy 256.

DM91RS

Too bad about the crank.

I thought that you had a set of 601's already prepped. Why not use those?

Later............. DM

kdrolt

Use the 350 gasket for the reasons you stated. Also look into finding a thinner head gasket, perhaps the one used on the L98 (aluminum head) Vette, because they are usually thinner than the one used on the iron L98 counterpart. A thinner gasket might help bump the CR back up some.

I also suggest some mild porting to the factory TBI intake. My neighbor removed the upper portion of the bore center-divider (then welded the exposed coolant passages closed) which helps the intake to act somewhat like a single/dual plane better than the stock configuration does flowing through the bore interconnection window (the window between the bores).

You can also smooth the corners inside the runners and remove any obvious casting flash, as well as radiusing the lower edges of the two bore cylinders. I also did more work on the lower plane runners because the lower plane doesn't flow as well as the upper plane does... in an attempt to equalize the upper/lower plane flow.

What should we call you now: Fast305 (again), or Fast355 (broken crank engine), or Fast312, or Fast383?

DM91RS

The GM composite gasket is around .028 thick. I used the one for the 350 on mine since the Vortec's have a larger valve than the stock 305.

The number is GM PART # 10105117 350 bore # 10105115 305 bore

Do you have the spec's on that cam you're going to use?

Fast.......uhhhhhhh what is it now?

Later DM

Fast355

iTrader: (2)

The reason I am going to use the 193s, is that I have switched over to a serpentine belt accessory setup and the 601s are missing a tapped hole.

I was thinking of grinding my performer RPM intake to use on the 193s and using my carb to TBI adapter on top. But woke up and have sinced decided to stay with the TBI intake and an EGR valve.

Cam specs are 212* @ .050" intake with .447" lift, 218* @ .050" exhaust with .454" lift. Its really a fairly mild cam that should be pretty easy to tune around.

In the end I am probably ending up with a 300 hp 305 that makes around 360 ft/lbs.

You'll can call me whatever you want.

DM91RS

I get your drift on the belts. I'm going to change to a serpentine setup on my wife's 84 Z28. I hate all those small pain in the butt belts.

Cam specs sound like a good choice. Is the 305 a roller block?

You would probably like to be called "done" and not have to keep changing engines......but it's interesting reading as you keep coming up with differant combo's.

Fast355

iTrader: (2)

No kidding, although it is interesting to see what works with each combo. Tuning the 350 was an interesting learning experience, even if the crank broke in the end.

The 305 is not a roller block or it would have gotten either a stock vortec 350 cam or the LT1 roller. The 305 is however the stock originol 4 bolt main block out of my 1983 G20. It has a steel crank, X steel rods, and flattop hypereutetic pistons.

DM91RS

quote:
The 305 is however the stock originol 4 bolt main block out of my 1983 G20. It has a steel crank, X steel rods, and flattop hypereutetic pistons.
quote:

That's the same engine that my son-in-law pulled from his 84 pickup. It has the 601's but I don't know about the bottom end. Are those rotating parts std for that assembly?

Fast355

iTrader: (2)

Those parts were stock for my application except for the hyper pistons. The factory pistons are regular cast flattops with 4 valve reliefs though.