I blew my 305 in my 87 Z28 and i just bought the GMPP 350 H.O. Now i noticed a few things:

1. My 305 has a vaccum line from the back of the q-jet to the booster. The 350 H.O with the holley 600 doesn't.....what do i do?

2. The 350 has HEI my 305 doesn't....will this be a pain during the swap?

3. My 700R4 in the car now is perfectly fine...BUT will it last with the large amount of power being thrown at it?

Any advice would be a very big help. Thanks
Paul

 

TTT....i need to know about this help me...anyone!

 

1. dont think i can help, i pluged everything exept one to the brake booster and one to the vac. advance.

2. i dont know what your 305 has if not a hei, is the dist from the 350 a one wire? if so all you need to hook up is the 12V wire and the tach. (it will have a two wire connector going to the incap-coil. (only))

3. no way to tell if a used stock trans of anykind is going to hold up. im not a big fan of the 700 but alot of people use them. the OD is nice for some. i broke a stock 400(stronger than 700) with my 350. i dont think a 700 unless redone will hold up that long.

 

The holley will have a vacuum port on the rear of the carb for the booster - there maybe a plug in it, and you may have to remove it and put a fitting in place - the holley carb instructions will point it out. Or, you can route vacuum off the manifold port to the brakes - choice is yours.

The HEI - you'll be removing the ECM altogether if using a holley carb - so the new HEI dizzy is needed - the 305 dizzy was computer controlled on the timing advance, and now you'll be vacuum controlled on the timing advance. The new HEI dizzy will need a battery lead, and a tacj lead - both are gotten from the wirepack that went to the 305 dizzy (a search here will tell you which colored wires to use - just put connectors on the ends and plug them into new dizzy).

The tranny - no way to know until it's done. My tranny was toast, but my 305 didn't have the muscle to tell, and with the 350 it slipped badly, so I had to have a rebuild. 700R4 can be rebuilt to handle to power - just have to find someone that can do it reasonably - if it's needed - but you won't know until after the fact.

You'll need to control the torque converter lock-up function now, since the computer will no longer be there - there are kits available - you have to drop the tranny pan, install new lock-up solenoids, and wires, and it's all controlled by a vacuum switch instead of the ECM.

Since you'll be there, you could also do the S-10 torque converter, it's a cheap alternative to getting a higher stall rating - stock is like 1300, the S-10 converter is like 2000 - I paid like $230 from GMPartsDirect.com for mine - about $150 savings over an aftermarket converter, although it's not the 3500 stall everyone talks about, I'm happy with it.

Replace the motor mounts, tranny mount, etc. with poly while your there - now's the time - during the swap you'll want to replace many things while it's easily accessible (no motor in the way).

I found it easier to pull the 305 with tranny attached, and drop my 350 with tranny attached - for several reasons:

1) I knew I was installing S-10 converter
2) I knew I needed to go into the tranny for the torque converter lockup kit
3) I knew I wanted to replace all those mounts with poly
4) I was installing a shift kit into my tranny

If pulling it this way - get a load leveler for the hoist - it's a lifesaver when dealing with so much weight being so unbalanced with the tranny sticking out so far from the hoist.

And - remove the radiator - Although it can be done, Murphy's Law dictates that the motor will slam into the radiator.

Consider a different fan control method - I hate the fan switch in the block - I never found one that works. I got a Flex-a-lite controller that probes in-between the radiator fins and I love it - my fans always come on when they are supposed to, and the controller starts the fans at 60% - reducing the initial load on the electrical system - it was like $80 from Summit.

Stickies, and the search button are your two best firends here.

And know that this won't happen in a weekend, or even a week - I'm just getting mine tuned, and I've been at it for 6 months (but I did a rear end swap, replaced all bushings/mounts, and I have limited time. Point is, you'll need mega patience, and almost as much cash! The little things will nickel & dime you to death!

Good luck - Let us know how it goes!