v6 to v8 swap

[junior3382]

My 4.3l has 195 hp, stock, and if the motor you have has 200hp...then... I guess I am looking at this like 75K30 was, does not seem worth the work. However, since you have the motor already, then I can see where you are coming from. I wish you luck bud.

[shadygrady]

if i remember correctly someone did a 4.3 buildup and used 350 pistons and rods and got massive power out of that 4.3. i think somewhere around the 400whp mark. for what your going to spnd to swap them over you might just be able to rebuild your 4.3 a little better. and you wont have to worry about the wiring harness or anything

I thought it was already identical to the 350 other than missing 2 cylinders.the rebuid kits are more expensive and a new 4.3 from gm is atleast as expensive as a v8 if not more.I dont trust remanufactured engines.Seen too many problems that friends had with them.A 400 rwhp v6 doesnt sound like a good daily driver to me.

My 4.3l has 195 hp, stock, and if the motor you have has 200hp...then... I guess I am looking at this like 75K30 was, does not seem worth the work. However, since you have the motor already, then I can see where you are coming from. I wish you luck bud

You must have the vortech 4.3,mine is an 89 non vortech.To go to vortech I would need ecm,wiring harness,intake,and all the sensors that go along with it.Trust me guys,I understand what you guys are saying I wish my boss` work truck would tear up somehow and he would sell me the 454 out of it.He has a 1990,tbi,cheyenne 454.Or I had the money for a built 350/383.I honestly just need a little more truck than I have and I dont want the note buying a new/newer one comes with.Plus I want to have the exp. with my son of doing this ,who gets his license in a couple of years and will drive this truck.
Depending on weather I go tbi or tpi I`ll be useing the LT4 OR ZZ4 Cam with 1.6 or 1.5 rr respectivly.The heads of coarse will have the proper head work to handle the valve lift between .476 to .510.Larger valves,better springs,retainers,3/8' studs, guidplates,hardened pushrods.I have a tpi unit.Tbi`s are all over the j/y.1 3/4" long tube headers,Larger injectors if it`s tbi.350 or 454 size,larger tb or bored out stock unit,prom reprograming.That should be good for around 250 to 270 flywheel hp.I still havent ruled out going carb.This is still preliminary.The bottom end has checked out great at the machine shop.After the heads leave the machine shop they will be bout as good flow wise as the zz4(113/083)heads.(same size valves,radius and bowl blend,clean up ports and port match,clean up cc,bump up c/r.)These are 081 castings.This can all be done pretty cheap by my friend.Much cheaper than buying new heads and without the guesswork in buying used heads.Not trying to tell any one they are wrong or argue with anyone.I `m convinced by seeing similar set ups that this will be a healthy 305.Know a guy running low 12`s in his 305 camaro n/a,all moter.Thanks fellas.Any exp with this will be greatly appreciated.

[shadygrady]

Well,in the meantime anybody know any decent bolt on mods that help the 4.3?

[mad_bomber]

any body know anything about stuffing a carbureted 454 into a 90 k1500? the truck has a mild 4.3 right now and i would like something ALOT bigger and badder.

[shadygrady]

I`d find a donor truck and get everything I needed.Depends on if you want to keep the cpu controlled tbi unit,go carb,or a port efi setup.Whats it gonna be used for?Gas aint getting any cheaper.It will fit,for sure,if it`s in a fullsizetruck.We got one at work.Tows 20,000 lbs cable plow on about a 30 foot gooseneck fairly easy.Tows 5 tons or so almost daily on a 17,00 lb trailer.Plenty of power/tourqe

[mad_bomber]

well i already have the motor. i couldn't pass up the deal i got the motor minus intake, carb, water pump, and the distributor for 100 bucks, and its from the '70s. i could really go any way as far as fueling goes seeing as how theres no intake, however i would like to go with crab. i know the tranny (NV3500, 5sp manual) will bolt up, but will it hold up? the other problem i'm having is the wiring, and how to get every thing to work. the reserch ive done says that the wiring harness is the same from the 4.3, a SB, and the SS 454. so i think i could do TBI real easily, but i'd rather go carb. any suggestions on what to do with any of my problems? or maybe enlighten me on a problem or two that may arise along the way with the build or the may pop up once the truck is done. any help would be AWESOME!

[shadygrady]

What year model and make truck you puting it in?You want it to go fast or pull hard?Are you going to rebuild it from the ground up?

[mad_bomber]

the truck im putting the BB in is a 1990 K1500 scottsdale, like i said it has a mild 4.3 right now (mild to me is 386 WHP out of a V6) and im going for bottom end with the BB i tow alot of cars and play in the mud so this baby has to have some balls and be fast. and yes i have to rebuild the motor form the ground up cause it was dismantled when i got it

[shadygrady]

It would be easy to keep it tbi,but you`d prolly get more or easier power out of carb.If you go carb you`ll have to ditch the in tank fuel pump for a carb friendly version.I`m interested in what some of your mods are to the 4.3.I have one in my truck and was going to do a v8 swap but with gas prices I may just keep the 6.I know it doesnt get much better mileage but with the right tune it can get decent mileage.I`m a member of another forum.It`s a third gen camaro dedicated tech site.They have many right ups on chevy engine swaps of all kinds and tbi to carb to port injection swaps or vica/versa.It is in cars but the basic engine stuff is the same with a lot of the same computers and harnesses used.May help you a good bit.Its Thirdgen.org

[Sneakysportsman]

Any motor that is carbureated will go into any 92 and back GM truck All gauges will work fine when hooked to thier respectable location. The trans will shift as it should. You will however have to remove the Service engine Light bulb. 93-95 has to have the original distributor, MAP sens, and a TPS sensor for the trans to function.

In the event you are swaping a V8 into a V6 frame there are a few mods that have to be done.
1. Some GM V6 frames do not have nuts inside the frame shell for the Motor Mount bolts to thread into. You will have to add these if your frame didn't make the update on the assembly line.
2. When changing from V6 to V8 you will need the appropriate PROM chip for the engine and year if using a TBI setup.
3. You will need the appropriate fuel injectors for the production engine size.

DO NOT waste you money on bolt on parts- they are all a joke to get your money. If they worked then you could add 100+ HP just buy visiting your fav parts house. ANY INTERNAL PERFORMANCE PART ADDED TO A TBI ENGINE WILL CAUSE YOU A HEADACHE UNLESS YOU HAVE A CHIP BURNING CAPABILITY AND THE KNOWHOW OF HOW TO RETUNE THAT ENGINE. The computer has specific parameters that it will operate on ONLY. If you change the cam you must change the fuel settings.
1. The engine will only flow what the TBI unit lets it flow unless you have it modified to flow more, It can be done but retuning IS REQUIRED.

Visit youtube.com and search 95 Chevy Truck Burnout, this truck is a built 350 with a small cam and a few other parts, It has a Holley 600 vac sec carb with a custom made TPS to help with the trans function.

I have thousands of dollars in bolt on parts from Vortec heads w/2.02in and 1.6ex to 89 TPI intakes and It takes unknown amounts of hours to tune one in right. A stock tbi computer in a truck WILL NOT run a TPI setup. With the added injectors it forces extra electrical load on the drivers that causes them to over heat and burn out.