my V8 swap -notes

SWAPPING IN A 305, 350 OR ANY OTHER SMALL BLOCK, POST THEM HERE.
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markmitchinnh
I sleep in my van
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Joined: Wed Oct 13, 2010 2:07 pm
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my V8 swap -notes

Post by markmitchinnh »

things that I had to change , modify or figure out- this is for anyone contemplating a swap from V6 to 350/305 V8
1. if you use 84 or older cylinder heads the TBI intake will need to be modified because the center intake bolts are at a different angle. You will have to elongate the holes to an oval shape. I am told a decent machine shop can do it for a price.
2. the bracket that holds the sensors on top of the intake (pass side) from the V6 is spaced incorrectly for the V8 intake.
I welded a piece onto it got it to fit and then drilled the hole. 3. frame side of motor mounts is useable but you will need to
use V8 mounts and a plate of steel 1/8 inch thick bolt this to the engine set engine mounts on to frame mount and mark where the motor mount will bolt to the steel. pull the engine back out drill the holes bolt mount to steel then reinstall engine using mounts, I found that using header bolts on engine mount is easier. 4. Get an oil dipstick from a full size V8 chevy van.
5. The fuel lines on my swap did not fit the V8 so I found a set of braided steel fuel lines in a 90's chevy truck and they worked much better and looked good too. I am using a set of exhaust manifolds from a 1994 tahoe and the V6 Ypipe does not fit so I had a custom Y pipe made up. 6. Another thing about pre 95 cylinder heads there is an accessory bolt hole in the upper left side of the pass side head missing so I had to make a bracket going from the intake down to this area so it would not cause any play in the AC compressor. If I think of anything else I will post it. Mark
Recently bought a 1989 Astro RS from Florida. Replaced stock engine witha 1997 5.7 vortec with TBI and replaced transmission with rebuilt 700R4 with mild shift kit.
Bought on Monday the 16th of April 2012
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Mr_Roboto
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Re: my V8 swap -notes

Post by Mr_Roboto »

1. if you use 84 or older cylinder heads the TBI intake will need to be modified because the center intake bolts are at a different angle. You will have to elongate the holes to an oval shape. I am told a decent machine shop can do it for a price.

This is 86-earlier. 87+ is TBI/Camaro TPI style. The exception to this is Corvette aluminum heads which are always pre-87 style.

2. the bracket that holds the sensors on top of the intake (pass side) from the V6 is spaced incorrectly for the V8 intake.
I welded a piece onto it got it to fit and then drilled the hole.

Not a bad way to go, few bucks saved if you didn't get one with your engine. My TPI stuff is all home made like this.

3. frame side of motor mounts is useable but you will need to
use V8 mounts and a plate of steel 1/8 inch thick bolt this to the engine set engine mounts on to frame mount and mark where the motor mount will bolt to the steel. pull the engine back out drill the holes bolt mount to steel then reinstall engine using mounts, I found that using header bolts on engine mount is easier.

I just paid for mounts, this is definitely cheaper.

4. Get an oil dipstick from a full size V8 chevy van.

I ended up with a Mr. Gasket Chromed one, but I have to pull the pan for it. This is way more "OEM" for certain.

5. The fuel lines on my swap did not fit the V8 so I found a set of braided steel fuel lines in a 90's chevy truck and they worked much better and looked good too. I am using a set of exhaust manifolds from a 1994 tahoe and the V6 Ypipe does not fit so I had a custom Y pipe made up. 6. Another thing about pre 95 cylinder heads there is an accessory bolt hole in the upper left side of the pass side head missing so I had to make a bracket going from the intake down to this area so it would not cause any play in the AC compressor. If I think of anything else I will post it. Mark

Interesting on the fuel lines. I didn't have too much issue with mine when I was fitting a TBI engine in, wonder why. It's odd that you had to get different lines, I've seen the braided ones before would make for a nicely finished setup that's for certain. I may have to look for a set for myself.

The accessory bracketry on the early heads is a pain. I've been fighting that for a while to keep the serpentine. Don't know why, but it's been a huge hold-up in the process. I've got the aluminum bracket, it sounds like you've got the steel one which would be way easier to modify.

Doing well so far. got her running yet? That's the real awesome part of it!

Topic author
markmitchinnh
I sleep in my van
Posts: 589
Joined: Wed Oct 13, 2010 2:07 pm
Location: Barrington NH

Re: my V8 swap -notes

Post by markmitchinnh »

I should have had it running but I do not have a garage and its been raining since Tuesday here. basically I have to hook up all electrical connections reroute one small heater hose and install the starter and that should do it. Mark
Recently bought a 1989 Astro RS from Florida. Replaced stock engine witha 1997 5.7 vortec with TBI and replaced transmission with rebuilt 700R4 with mild shift kit.
Bought on Monday the 16th of April 2012

Topic author
markmitchinnh
I sleep in my van
Posts: 589
Joined: Wed Oct 13, 2010 2:07 pm
Location: Barrington NH

Re: my V8 swap -notes

Post by markmitchinnh »

I have also found that V6 throttle cable bracket does not work for my application because the cable does not reach the TBI. I am going to a u pick it yard tomorrow to get the brackets I need. I also have to get the lines for the rear ac from a full size V8 van with rear ac.
Recently bought a 1989 Astro RS from Florida. Replaced stock engine witha 1997 5.7 vortec with TBI and replaced transmission with rebuilt 700R4 with mild shift kit.
Bought on Monday the 16th of April 2012
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