Vortec 5.3 swap

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allan man

allan man

10 Year 15 Year
Joined
Mar 9, 2008
Threads
249
Messages
2,246
Location
Las Vegas,Nevada
Im gathering parts slowly for the upcoming swap on my 74 FJ40
2004 5.3 Vortec from a silverado will i need to change the oil pan from a camaro for things to clear?

SOA
OEM springs
AA Bellhousing
H41
oem TC
 
I'm going the same route as you, 03 tahoe 5.3 - SOA, high steer, H42 trans and stock transfer.
Getting the harness and computer from Howell. They are great to deal with.
 
Welcome to the electonic age! 2X on Howell's - They have a nice engine/ECM harness and stand behind their stuff.
 
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I'm using a rear sump pan for my SBC.

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And an Advance Adaptors motor mount kit. Notice the offset on the mount to align the engine with the stock running gear.

Top photo is drivers side. Bottom photo is passenger. If the engine was centered both bolts would be in the third hole in. But they are shifted towards the passenger side by one bolt hole. These holes are spaced one inch apart, center to center, so the engine is offset by one inch. I think the factory offset is supposed to be 1.5". My block huger headers had to be dimpled on two tubes to clear the steering box, so they could have used that extra .5".
 
thats a good swap to do mate, we've just swapped out the old carbed sbc 350 in my FJ75 cruiser for a 6.0 litre silverado vortec, with your 5.3 engine coming out of a silverado wouldnt it already have a rear bowl truck oil pan? When we did my swap we used the same aussie dellow bellhousing from the SBC, there was 1 bolt hole we had to skip that isnt tapped on the rear of the vortec block, bolted on an LS1 flywheel and my mate made up a twin plate clutch out of a 2F pressure plate and 2 clutch plates and bolted it all up to the H55 box, we had to shift the engine mounts back about 50mm, we had a couple of chopped up wiring looms that came with the engine and my mate traced through it with a wiring diagram and rewired it and we got a reflashed GM computer through spareECM in the states and it all started up and ran... goes like a cut cat and smokes the tyres up in third gear :steer:




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Last edited:
sadam_husain: Why the 2 clutch plates?
I see that spacers were used to stand the pressure plate off of the flywheel. wouldn't using the Toyota clutch for the H55f and the chevy pressure plate eliminated the double clutch plate?

When I did my SM420 conversion to the 2F in my FJ40, I used a 10.5" GM clutch plate and a stock 2F pressure plate and throw out bearing and everything bolted up. Just seems that the dual clutch plate overly complicates the installation.
 
X3 on Howell and I too didn't have to swap the pan. I did/ do have SOOOOOOPER CLOSE to the trans pan. It's a 4l60e though.

You're gonna LOVE that motor!!!
What a difference! I'm on 37's and 4.88 ring gears and I average 14.85 MPG.
Not bad considering I was BARELY getting 10 in my 62.
 
Howell it is....How much would i expect for the PCM and wiring harness? would it be less money considering i wont be using the 4l60e.
I would also like to swap out my throtle body to a cable instead of the module throtle body,any input on what vehicle i should be looking for to interchange as a direct swap to do this would be appreciated.Thanks you all for the responses:)
Also will the old school ram horns center dump manifold work on the vortec?
 
allan man said:
Howell it is....How much would i expect for the PCM and wiring harness? would it be less money considering i wont be using the 4l60e.
I would also like to swap out my throtle body to a cable instead of the module throtle body,any input on what vehicle i should be looking for to interchange as a direct swap to do this would be appreciated.Thanks you all for the responses:)
Also will the old school ram horns center dump manifold work on the vortec?
Click to expand...

Check http://howellefi.com/

It looks like using a non-computer controlled transmission will save you $50 for the wiring harness.

I am not seeing any harnesses with a mechanical throttle control for the later Vortec motors. The LS motors used by 'Vettes seem to have an option for it though.
 
Lil John could help more with this, but there were folks who had a LOT of issues getting the PCM reprogrammed to jive w/ the manual trans. Just do your research first.
Howell is not the cheapest option out there, but they are the one company that I have not heard a bad thing about. They came recommended to me from a number of reputable builders including orangefj45. IIRC, I paid around 750 for the harness, O2's and MAS, and ECM (w a core)
Be sure to tell them what your planning to do w/ the manual trans and I'm sure they could help you out.
The only issues I had w/ them, was the were a bit skimpy on the dirrections and the MAS split in half. I told em about the MAS and the had me ship em the old one and they just shipped me a new one even though it was 8 mos. after I got it.
Nice thing is... It's clearly labeled, sectioned out and PLUG AND PLAY!! Easiest part of the build.
The old style cast ram horn won't work as the patterns are different.
I uses the AA headers on mine. It fits tight, but I've not had any conflicts.
Here's a couple pics of the motor on and wired.
I'm stoked for you!!! It's a great mod that will improve every experience you have driving or wheeling you rig.
Can't wait to see this get going!!
I'm pretty certain that the tb housing can be converted to accept the cable drive at the throttle. I used a lokar throttle cable kit for that set up.
Any help I can offer, lemme know!!
Just got done w/ this, so it's still pretty fresh.
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Tigerstripe40 said:
sadam_husain: Why the 2 clutch plates?
I see that spacers were used to stand the pressure plate off of the flywheel. wouldn't using the Toyota clutch for the H55f and the chevy pressure plate eliminated the double clutch plate?

When I did my SM420 conversion to the 2F in my FJ40, I used a 10.5" GM clutch plate and a stock 2F pressure plate and throw out bearing and everything bolted up. Just seems that the dual clutch plate overly complicates the installation.
Click to expand...

twin plate clutch coz anything else would slip, the centreforce clutch with a dual friction plate in my other cruiser behind a sbc 350 is good but no where near as strong as the twin plate clutch in this truck, it was a lot of mucking around building it and getting it all to fit but well worth it in the long run :hillbilly:
 
I have a 6.0 liter in my 40 with a 12" old school chevy clutch and it does seem that if you really give it WOT the engine makes enough power to slip the clutch but only at the top of second gear. It holds well in all other gears under hard throttle. But when you rap it out in second you can feel the clutch loose hold just before it hits the rev limiter. the smell gives it away every time.
 
Any one have any pix using the H41? I just dropped my 5.3/h41 in and the shifter is 4" forward with the engine shoved all the way back.
 
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