Author Topic: Thinking of building a 4.3 (Read 8871 times)

SWAMPER · « **on:** Oct 18, 2007, 09:04:50 PM »

Just like the title says im thinking of dumping a 4.3 into my 85 simply because i can get one for pretty cheap unlike a 3.4, the thing is that it comes stock with 190hp and yeah thats fine and dandy but us being the altering kind of ppl that we are i cant seem to just drop that in...i want to pump out around 250hp atleast nothing too crazy because i still want so so gas milege, so what do you guys recommend to upgrade and swap out to be able to have that kind of power im not to familiar with the HP scene thats why im asking....also if you have any experience with the swap it like to hear from you thanks guys $Beer Chug\'n$

brainlessfool · « **Reply #1 on:** Oct 18, 2007, 09:36:41 PM »

Hey guy, I was going to do this for my 83. but got rid of the motor. did not want my son leaning to drive a jack up high hp top heavy truck. so stayed with the 22R

250? well it could be done. butt frist I would drop it in as is with a set of headers.
bet you'll be fine with it like that.

not as much out there for the 4.3 as the 350.
did find some cams (roller by the way) and at least one intake. butt if you get a vortec i'd be happy with that and a set of headers.

Wermz84 · « **Reply #2 on:** Oct 18, 2007, 09:40:08 PM »

What would you be thinking of to upgrade your Tranny and Axles?

SWAMPER · « **Reply #3 on:** Oct 18, 2007, 09:51:10 PM »

tranny and axles? no that will stay the same i mean like change on the motor to get more hp...

brainless thanks for the input ive read of ppl pumping out 300hp out of the 4.3's so i know 250 is very doable im just wondering how to reach that as for now i think headers, cam port and polish the heads, i want to put a snorkel on it so no air intake thing

Wermz84 · « **Reply #4 on:** Oct 18, 2007, 10:11:43 PM »

Not sure I made myself clear.

I was wondering if you were going to put a beefier tranny behind the 4.3 to handle the larger power output.

250 shouldn't be to hard to reach.

SWAMPER · « **Reply #5 on:** Oct 18, 2007, 10:14:29 PM »

oh id get the marlin HD tranny but the axles should be fine

red · « **Reply #6 on:** Oct 18, 2007, 11:58:08 PM »

should be just fine with a marlin tranny and your t-case. check out summitracing, are you looking for top end, middle, or bottom end for your power band? knowing which rpm range you plan to have your maximum power at will change your cam, headers, and intake manifold selection. building for the middle range (2400-3500rpm's) will also help your fuel economy. building lower/middle will both be great around town but if you build for the upper rpm's you (usually) wont have hardly any power until you reach 3000rpm's, i would not recommend building for upper since this is a trail rig.

are you going with carb, tbi, or vortec because again this changes things. holley is the only company that i'm aware of that sells higher flowing tbi units. if your going carb, edelbrock is the only company that i would recommend for a gm motor. the stock carb is a quadrajet, works pretty good (most fuel efficient when tuned right), but is a pain in the ass to adjust and is more tempermental on steep angles.

usually if you order parts together from summit they give discounts, look through their catalog and they will list specials on things like this. example (not a current package that i know of), rebuilt heads that are ported, carb, and intake manifold for 870 bucks. total without the package would be around 1100 or so.

SWAMPER · « **Reply #7 on:** Oct 19, 2007, 10:05:42 AM »

thats some good info red thanks

im pretty much going with lower to middle range...and it will eventually be a trail rig but this is what im driving until i ship out to iraq then im thinking of buying a new camaro when i come back

haha oh and im going vortec

Hammerhead · « **Reply #8 on:** Oct 19, 2007, 11:27:59 AM »

Quote from: red on Oct 18, 2007, 11:58:08 PM

...if your going carb, edelbrock is the only company that i would recommend for a gm motor. the stock carb is a quadrajet, works pretty good (most fuel efficient when tuned right), but is a pain in the ass to adjust and is more tempermental on steep angles...

I strongly disagree with this statement. (Sorry Red) I've run about every carb in the book and none of them will perform as well as the Quadra-jet for offroad use where bouncing and tipping to extreme angles is involved. You couldn't pay me to run one of those PITA POS edelbrocks again. I'll take a Q-jet anyday...

You're best bet is fuel injection. Beats the crap out of any carb!

Hammerhead · « **Reply #9 on:** Oct 19, 2007, 11:32:19 AM »

Oh, yeah, 250 HP is doable with a 4.3. My engine builder friend says a 4.3 is every bit as buildable as a smallblock. It just doesn't have 50 years worth of aftermarket hot rod parts to back it up.

red · « **Reply #10 on:** Oct 19, 2007, 02:35:15 PM »

the quadrajet carb on my 305 in the 81 gmc pickup i had was a pain in the rear (their always either one way or the other, great or a pain that i've noticed). i had good luck with an edelbrock (mostly in mud and on dirt trails).

but i agree on the 4.3 being very buildable. most buildable v6 on the market. since your going vortec pablo your gonna need a vortec intake manifold and heads, these parts dont line up right with their carb/tbi counterparts (more power with the vortec anyways and the multiport fuel injection). ask yourself if your gonna be idleing-just above idle (2000rpm's or less), or if your gonna use the skinny pedal when your crawling. you might loose some fuel economy if you build for bottom end, but you wont have you use the gas pedal as much either.

FIREBALL · « **Reply #11 on:** Oct 19, 2007, 02:52:11 PM »

Just saw a 91 4.3 on chico craigslist for $400. Says it's still in the rig and you can hear it run. I paid $850 for my 93cpi.

SWAMPER · « **Reply #12 on:** Oct 19, 2007, 11:03:44 PM »

ive seen em here for around 200

so i k now it will be a tad cheaper but yeah i am going vortech i figured if im putting in a different engine might as well do it right and get an efi

red · « **Reply #13 on:** Oct 20, 2007, 12:20:34 AM »

good thinkin

. usually the staff at summitracing is pretty knowledgeable, contact them and let them know what your goals are, whether it be building the bottom end, middle, going to 250hp, looking for good fuel economy, etc. 250 can be easily reached with the 4.3 vortec without compromising reliability.

FIREBALL · « **Reply #14 on:** Oct 20, 2007, 08:20:03 AM »

Definetly do some research before you buy a motor. There were very few performance parts for my cpi motor. The throttle bodies had much better aftermarket support.

bigarms23 · « **Reply #15 on:** Oct 20, 2007, 11:10:53 AM »

I was talking to my buddy and he has a 924runner with a 4.3 and he done the following to his engine bored .20over k&N filters and a hypertech tuner he says he has 265hp but i dont know for sure

SWAMPER · « **Reply #16 on:** Oct 20, 2007, 04:43:42 PM »

fireball i had heard the same about the throttlebody....might have to look into that too
thats sweet bigarms i had forgotten about the hypertech tuner's good to go

RockSlayer · « **Reply #17 on:** Oct 23, 2007, 11:15:12 PM »

There is a version of the 4.3 that was 230 HP from the factory. I think it is the CMFI motor out of the 96 and later Astro van. And I think the 4.3 in the typhoon was something like 265 hp, but I think that was a very conservative figure since the Typhoon ran 12's in the quarter.

mudmaster · « **Reply #18 on:** Oct 24, 2007, 08:17:13 AM »

I believe the Typhoon had a Buick motor

3.8

LOL @ IFS · « **Reply #19 on:** Oct 24, 2007, 09:52:44 AM »

The SyTy trucks had LB4s, which were the Vortec 4.3's.

SWAMPER · « **Reply #20 on:** Oct 24, 2007, 12:28:47 PM »

haha good luck finding one of those in the junkyard and it ran the 1/4 mile in 14.1 secs and 95mph and it was turbo charged

*96 and later astrovan thanks man im deff cheking that out*

*ROKTOY* · « **Reply #21 on:** Oct 25, 2007, 07:57:53 AM »

If you want 250 hp why not just put a 350 in? After you do the work to the 4.3 gas mileage won't be much better. You will save money in the long run and will always have more hp & torque to boot.

SWAMPER · « **Reply #22 on:** Oct 25, 2007, 12:31:30 PM »

because i know myself way too good and if i get a 350 id just end up hopping it up to like 400hp and i dont really want to have to get new axles tranny and all that good stuff

*ROKTOY* · « **Reply #23 on:** Oct 25, 2007, 01:15:45 PM »

Well that being said a 4.3 won't do it for ya for long.

SWAMPER · « **Reply #24 on:** Oct 25, 2007, 01:18:27 PM »

oh ill be satisfied thanks for the worries $Beer Chug\'n$ lol

Ferg · « **Reply #25 on:** Nov 03, 2007, 06:39:42 PM »

Quote from: toyguy86 on Oct 25, 2007, 01:15:45 PM

Well that being said a 4.3 won't do it for ya for long.

Really? I've been running mine for over eight(8) years with a W56 behind it and 35s. Fordyce, 'Con, TDS, and until recently my daily driver.

Holds up just fine!

SWAMPER · « **Reply #26 on:** Nov 04, 2007, 04:22:47 AM »

well he meant that it wont satisfy my thirst for upgrading

topar · « **Reply #27 on:** Nov 04, 2007, 06:10:18 AM »

I run a 350 with a 650 eldebrok off road carb it works great. I use a turbo 400, Danna 300 and Toyota axles welded f/r with 5.29 gears. Love it

*ROKTOY* · « **Reply #28 on:** Nov 04, 2007, 08:59:37 AM »

Quote from: SWAMPER on Nov 04, 2007, 04:22:47 AM

well he meant that it wont satisfy my thirst for upgrading

Exactly

SWAMPER · « **Reply #29 on:** Dec 24, 2007, 11:04:05 AM »

so for the guys out there with the swap...what exactly do i have to modify to do the swap i know i need an adapter for the tranny but what about engine mounts and all that

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