Swap 305 to 350 but keep stock manifold and carb?

[TechBill]

I have a 1986 C10 Custom squarebody truck. It have 305 with a Quadrajet carburetor that is plugged into a computer behind the glovebox I think. I am not sure what exactly it is yet but I think it have something to do with distributor cap.

The engine and carb is no good because the hood was stolen off of it and rain water gotten into it rusting everything out. So I got another Quadrajet carb that have a computer plug on it and I was plan on rebuilding the 305 in it.

But a friend of mine recently told me I could have his 350 out of his late 70's Vette and he think if I take the manifold and carb off the stock 305 it should bolt directly on it and drop in the truck without modification but he wasn't sure about the computer if it need to replaced or reprogrammed etc.

I wanted to keep it stock as much as possible so would it work just swapping the block but keeping everything else stock or is there something I need to change on it?

Bill

[Dead Parrot]

The intake manifold is a direct swap. No difference between 305 and 350 assuming both are SBC motors. Transmission should be compatible. Not sure when they switched from two piece rear seal to one piece and how that impacts flex plate, if it does.

What motor was the 2nd computer carb from? Even if plug compatible, it might be calibrated far different then what is needed for a 350.

No clue on computer compatibility. Most computerized thing in my 75 is the AM/FM cassette stereo.

[TechBill]

Originally Posted by Dead Parrot

The intake manifold is a direct swap. No difference between 305 and 350 assuming both are SBC motors. Transmission should be compatible. Not sure when they switched from two piece rear seal to one piece and how that impacts flex plate, if it does.

What motor was the 2nd computer carb from? Even if plug compatible, it might be calibrated far different then what is needed for a 350.

No clue on computer compatibility. Most computerized thing in my 75 is the AM/FM cassette stereo.

I brought the replacement carb on Ebay from this seller

http://www.ebay.com/itm/Rochester-Qu...53.m2749.l2649

I brought this one because it shows that manufacture number matches what on my rusted carb which is 17085226.

I will take a picture of my old carb number and upload it here from my phone.

[TechBill]

Here photos of my old carb

[100%Chevy]

Put all the 350 in it(carb,intake and distributor).
Then just leave the computor connector hanging.
You'll never miss it!
I did the same to my 82,K-10 when I put a 454 in it.
Mike.

[TechBill]

Originally Posted by 100%Chevy

Put all the 350 in it(carb,intake and distributor).
Then just leave the computor connector hanging.
You'll never miss it!
I did the same to my 82,K-10 when I put a 454 in it.
Mike.

My friend is keeping his manifold, carb and the value covers from the 350 he giving me. So I will have to use ones from my 305. That why I am asking here if i could use ones from my 305 since it a computer controlled carb and distributor.

But the 350 includes the roller lifters and roller rockers which he letting me have and keep.

Bill

[geezer#99]

Here's some things to be aware of.
If the 350 has roller lifters then it's likely a one piece rms and requires a different flex plate for the tranny. Plus your distributor drive gear isn't compatible with the roller cam.
Also there might not be a mechanical fuel pump on it. You might need an electric one.
Plus some roller rockers won't fit under your stock valve covers.

[TechBill]

Originally Posted by geezer#99

Here's some things to be aware of.
If the 350 has roller lifters then it's likely a one piece rms and requires a different flex plate for the tranny. Plus your distributor drive gear isn't compatible with the roller cam.
Also there might not be a mechanical fuel pump on it. You might need an electric one.
Plus some roller rockers won't fit under your stock valve covers.

Thank for the head up.

He said the motor came from his late 70's Vette so I haven't seen it yet and I don't know what it got on it yet.

I just hoping that it will drop in nicely in my truck, I really missed it and haven't drive it since 2005.

Bill

[Dead Parrot]

Keep all of the parts from the old carb. The primary rods and jets are brass and clean up nicely. Certain secondary rod hangers and rods are highly sought after. You never know when you might need some little hard to buy part that you can salvage from your old one.

Find out from your friend if the roller lifter setup was factory or aftermarket. Then verify distributor gear compatibility. Distributor gears are fairly easy to change.

You can wait on the valve cover question until you get the 350 and can test fit yours.

[TechBill]

Originally Posted by Dead Parrot

Keep all of the parts from the old carb. The primary rods and jets are brass and clean up nicely. Certain secondary rod hangers and rods are highly sought after. You never know when you might need some little hard to buy part that you can salvage from your old one.

Find out from your friend if the roller lifter setup was factory or aftermarket. Then verify distributor gear compatibility. Distributor gears are fairly easy to change.

You can wait on the valve cover question until you get the 350 and can test fit yours.

Thank you for the advices. I will check on those things

[TechBill]

What about the computer behind glovebox? I think it only controls the distributor but will it work with 350 if I use same dist from 305?

[Jaysonb]

The spark control set up is a failure prone item, best to just use a regular hei distributor. The carb isn't computer controlled, it just gave the engine more fuel with the accelerater pump shot when not warmed up, and it will work fine not hooked up.