350 or 454?....the milage question....

[iluvmy72]

OK I FINALLY got the wife to stay away from the mini-van thing. Now we have this cinario shaping up and I am not quite sure on everything....Have 2 suburbans....one is a 96 1/2 ton....another is a 94 3/4 ton with a 7.4 that needs a top end rebuild....we got the 96 to replace the 94 in order to put in a gas saver engine in the 5.7 vortec as compared to the 454 in the 94. Well I trashed the 96 in a wreck but the engine is still good. I could put it in the 94 and go from there(yes I know that is a wireing beast of a job), put in a TBI 350 with Vortec heads from the 96 5.7 motor, keep the 454 stock, or put vortec heads from a vortec 454 motor onto the current TBI.

What would my real gas savings be between all of this?

[mbgmike]

Originally Posted by iluvmy72

OK I FINALLY got the wife to stay away from the mini-van thing. Now we have this cinario shaping up and I am not quite sure on everything....Have 2 suburbans....one is a 96 1/2 ton....another is a 94 3/4 ton with a 7.4 that needs a top end rebuild....we got the 96 to replace the 94 in order to put in a gas saver engine in the 5.7 vortec as compared to the 454 in the 94. Well I trashed the 96 in a wreck but the engine is still good. I could put it in the 94 and go from there(yes I know that is a wireing beast of a job), put in a TBI 350 with Vortec heads from the 96 5.7 motor, keep the 454 stock, or put vortec heads from a vortec 454 motor onto the current TBI.

What would my real gas savings be between all of this?

can't help on the big block,but i get right at 16 mpg on mine(350)

[Boog]

I don't see the return for the amount of headache and work you'll put in doing this swap. I might suggest repairing the 7.4 and keep going or sell both trucks and buy a newer one with 5.3 and 3.73 gears. It's a good combo.

[iluvmy72]

NO WAY!!! the 94 has been our baby.....here is the reality....I own the 94. I can't afford a newer one with a 5.3. However I can always do that swap later and the 94 already has the 3.73 ratio. But I gotta also be honest here as well. I very much dislike the 2000-2006 body style including the stying of the interior. The interior also feels smaller. The seats don't seem to be as "plush". But then again I liked the styling of the 73-91 the best. Just hated the front bench seats. I love how open the front dash area is on the 94. Plus here in Utah you need 4WD. Push button 4WD was never my favorite setup. And most parts on the 94 are cheaper to repair compared to the newer ones. Example: fuel pump.

[Hoods69BadBowTie]

I would dump the 454 and just put a 350 in there or if you really want to keep the 454 do the vortech heads swap. Don't think your going to do much with mileage on the swap. If you really felt like doing the wiring swap you could do it. If it was me I would just do a TBI 350 swap sum heads and intake on but thats just me.

[iluvmy72]

well on that same note, I'm wondering if I can take that same 5.7 from the 96 and put it into the 94 with a tbi setup controlling it. But I have never tried it. However it would get rid of the stupid poppet valve thing and plastic intake.

[texasfunk]

Originally Posted by iluvmy72

NO WAY!!! the 94 has been our baby.....here is the reality....I own the 94. I can't afford a newer one with a 5.3. However I can always do that swap later and the 94 already has the 3.73 ratio. But I gotta also be honest here as well. I very much dislike the 2000-2006 body style including the stying of the interior. The interior also feels smaller. The seats don't seem to be as "plush". But then again I liked the styling of the 73-91 the best. Just hated the front bench seats. I love how open the front dash area is on the 94. Plus here in Utah you need 4WD. Push button 4WD was never my favorite setup. And most parts on the 94 are cheaper to repair compared to the newer ones. Example: fuel pump.

Mu old 99 tahoe had the 5.3 and it was lbs. I loved it.
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