Hello,
currently in my '86 Iroc I have 305 LG4 with Edelbrock Performer intake and 1405 carb, shorty headers and guy told me that cams are different too, but I don't know about that.
I would like to put here a 350 sbc block while keeping the carb setup, so I have to search for pre-86 blocks to make it work, but are there any other things I should look for while searching for the new block to make if fit? Would aprreciate any hints. How much hp could I get with this setup on 350 pre 86? Or should I just sell the whol engine and do the LT1 swap which I don't really want to.
Would the headers I have now fit to the 350? What other parts from 305 fit to the 350?
I have 700R4 and in the future maybe conversion to 383 on my mind.
Thanks!

 

Cams are usually different... the OE LG4 cam, you can completely hide the bumps with Clearasil. Most any other cam, they're more visible than that. Might even take a training bra or something heavy-duty like that.

You don't necessarily need a pre-86 block. 86-up blocks merely use a different flex plate. Very few $$ to make the swap.

EVERY SINGLE other part of your 305 "fits" the 350. ANY Chevy SBC 350. (except of course LT1) Yes your headers fit. Your water pump, alternator, starter, carb, etc. etc. etc. ALL will swap right over to ANY 350 other than LT1. Your intake might even swap over, but that would depend on whatever heads you end up with bolted to whatever block. There's no correspondence between "block" and "intake" in that regard, only heads and intake.

It's well nigh impossible to "sell" a 305. ANY 305. They're hard enough to give away. I usually have to pay to have em hauled off. Which is to say, their "value" is THE OPPOSITE of "sell". Kinda like, I don't think you can "sell", let's say, your socially transmitted disease, to a doctor, can you? You pay em to rid you of it. 305 is in the same class of things.

If your car has an auto trans, it's a 700. No need for "future maybe conversion" there.

 

'86 was a transition year. It had a flat tappet cam like previous years ('87 went to roller lifter cams in passenger vehicles, but not trucks), but was the first year for one-piece rear main seal cranks (same flexplate as all later years, different from 2-piece rear main seal cranks of '85-earlier). So, an '86-later 350 would not require a different flexplate.

One possible problem is some of the later EFI year 350s didn't have the fuel pump push rod & drain holes machined. If by chance the 350 you find falls into that category, you're going to have to rig up an electric fuel pump one way or another.

Horsepower is impossible to predict. There were so many variants of 350s, and the majority of factory 350 heads made were horsepower junk - like the 305, worth more at the scrap yard than at the swap meet.

Too bad your car was converted over to non-CC carb (assuming this is a US-delivered car). The CC q-jet works great on a street/performance 350.

Again assuming this is an originally-US-delivered car, how is it set up to lock of the TH700R-4 torque converter clutch with the Edelbrock carb? If it isn't, your tranny isn't long for this life. Ditto the TV cable connection to the carb throttle arm - it needs a geometry-corrector bracket to properly control internal transmission pressures.

 

I have a 350 in my 85 and I’m curious to figure out if the guy I bought the car from put the wrong water pump because I was told the car had an original 305 with a carb and intake manifold put on it but to my conclusion it’s a 350

 

"Water pump" is not a function of 305 vs 350. The same accessory drive systems fit both. The WP goes with the accessory drive system.

The head casting you have, came on TBI 350s such as trucks and Caprices. Your block says 5.7 so it's a 350 as well, might conceivably be a whole factory motor, not likely but not impossible either from what you show. Probably 99.99% of all motors used in a swap like this aren't factory motors though; they're "rebuilt", which means that all the parts and pieces have been randomized to some extent. Which in most cases matters very little or not at all to anything external to the motor proper (like ... water pumps) since they're all so similar. None of that has anything to do with which water pump is right for your setup or which one the PO put on it.

Why does your water pump seem wrong?

 

[QUOTE=sofakingdom;6429622]"Water pump" is not a function of 305 vs 350. The same accessory drive systems fit both. The WP goes with the accessory drive system.

The head casting you have, came on TBI 350s such as trucks and Caprices. Your block says 5.7 so it's a 350 as well, might conceivably be a whole factory motor, not likely but not impossible either from what you show. Probably 99.99% of all motors used in a swap like this aren't factory motors though; they're "rebuilt", which means that all the parts and pieces have been randomized to some extent. Which in most cases matters very little or not at all to anything external to the motor proper (like ... water pumps) since they're all so similar. None of that has anything to do with which water pump is right for your setup or which one the PO put on it.

Why does your water pump seem wrong?[/QUOTE. I was told when I bought the car it was a 85 rs with a 305 after tuning numbers it came back as a camaro with a few z28 options now I I went under the hood to see what the the block read now as u see it came back 5.7 now the guy I bought this car from said it was runnin a lil hot but wasn’t to sure how acturate the gauge was now he replaced the radiator replaced the pump and took out the thermostat now I was told that the 305 has a reverse flow water pump by two guys that say they know this but I can’t get any directions on identifying this from the correct 350 one do I just pull the old pump off that I have on it and just open it up and check the hope file for the best with this new 350 pump I got

 

Jesus.

 

thank u so much the info was very helpful I’ll let u know the outcome

 

Repeat after me:

There is NO DIFFERENCE between a 305 WP and a 350 WP.

OK, now that we've got that out of the way...

There IS a difference however, between the WP for a 305/350 with serpentine ("snake-like") belts, and WP for 305/350 with traditional ones. Specifically, they turn the opposite way.

Therefore the choice of WP depends on what accessory drive system you have, NOT 305 vs 350. (which incidentally, I found the block casting # in your pics, it's 638, which is a 350) And, not the heads, not the block, not the PO's diarrhea of the mouth. Only on the accessory drive system.

Which one do you have? Do you have the correct WP for that system?

 

I am guessing that someone told him that the Water-Pump was a "Reverse-Rotation" Pump for Serpentine-Belt Accessories...
and now he is confusing Reverse-Flow Cooling-Systems (like the Gen-2 SBC Engines) with "Reverse-Rotation" Water-Pumps.

 

Ah, I see that @sofakingdom was thinking the same thing.