KLR650-Guy

I have a 2008 Silverado with the 4.3 V-6 and 4 speed auto. I want to know what mild built 350 or 383 will fit with this transmission. I am thinking 350HP and a mild cam. Any help would be appreciated. I plan on buying parts and building the engine and replacing the 4.3 when I get the truck paid off next year. Sounds like a plan to me anyway. I am leaning towards a GM crate engine, maybe the 350 HO or something similar. I figure that transmission can handle a factory 350, it can handle a little more power. May build it too if I get a hot enough engine... Just looking to build a fun driver. Nothing that will ever get raced.

I built a 380 horse straight six a few years ago for my old ford, but I wrecked that rascal the first time I took it to a drag strip. Its a beast. Carbs are a bitch. Triple deuce side draft intake, bored and stroked and cammed! Still have the engine would like to build a rock crawler around it someday.

Thanks guys!

silverado08

on an 08 there will be many wiring and computer probs with swapping out for a different engine. if your wanting 350HP, it would be a lot cheaper to just put a turbo on it and some internal engine upgrades. I've seen the 4.3L putting out 500HP.
If your truck was older it would be easier for an engine swap, but i don't recomend it.

KLR650-Guy

I have researched it some, and I know a current production 5.7 will fit on the same motor mounts, and bolt to the same transmission. My only problem is that I want an older carb engine. Is this doable? I have seen it done with an 04 silverado.

racerx55

IF your going carb route, you might as well get yourself a built 700R4 (if you want to keep OD) and just do it all the old school way.
IMO it would be more fun to have a turbo 4.3L, and still get as decent of mileage as you get now.
you can get a ton more power out of a newer style engine and fuel injection, and still be much more driveable. Consider a 6.0L SS engine swap. they make a good amount of HP and you still get better than 3mpg.

xpeder

why did you buy the truck with a v6 and want to go back to carb route fuel injection is better

cams 98 silverado

dude. go get an escalade high output 6.0. stock makes almost 400 horse. its like 360 hp. best part of that is you can get the motor with full harness for under 1900. i see them on ebay for 1700 sometimes. its a simple swap. them ls motors kick the hell outta old school. if you really wanna go carbed then my opinion is you will have a lot of issues with the computer... the best and most honest information i can do is www.performancetrucks.net if teh adminz dont mind me posting this link. well go to it. believe me that site. will give you every answer you want with your truck...

maxxman04

i agree. the headache involved with swapping in a 350 just isn't worth it. the 4.3 is a 350, just minus 2 cylinders. turbos, nitrous, ignition upgrades, cams. all alot easier to do. as for goin back to carb, why? fuel injection is far superior to making power and economy. i did a swap to carb on a 94 silverado, found it was not worth the headache. you might also be able to find a donor truck with a v8 in it, and do a full computer, harness, motor swap. otherwise, go to town on the v6.

desrtrat

find a 6.0-6.2L mild cam, wire harness, ECM, exhaust, and have a nice day

KLR650-Guy

Ok, well thanks for the info guys. Heres the deal, I bought this V6 truck just over a year ago and only paid $12,900 for it. Its almost paid off and I originally bought this truck to be a project. I am going to build a stroker and get a turbo 400 or something similar and pretty much gut the truck. If I wanted economy and modern engineering I would have purchased a Prius and not an old school V6. Again, thanks for the imput... anyone want to buy a 4.3 and a 4 speed auto? It has 11,290 miles and it will be yanked out this weekend.

maxxman04

a bit of info that might have helped. you didn't really state your intent with the truck. since you are going to gut it, the possibilities are endless. though, a turbo 400 isn't really the trans of choice for a mild small block and daily drivin. 700r4, 4l60e, will keep the overdrive and still handle the power just fine. if you're not worried about the overdrive, then stick with a turbo 350. 400's are power eaters, and unless you are racing or abusing the trans with serious power, it's a waste. t350 will handle your 350hp-400hp+. good luck