I'm in fl an there's airboats running 4.3 pushing 400 horse an there holdin up it can be done I'm not asking for 400 horse just in the low 200s

 

If you get a good set of vortec heads I beleive you gain an additional 20hp.Your going to spend $500 on aftermarket carbed manifold to fit them.You will spend $3-$400 on a new carb.Your going to need a better distributor not sure how much they cost.If you have alot of cash to sink into this it can be done.As said before its cheaper to go with V8 swap.

 

Ill have the carb taking care of as of right now I'm running a 600 Holley distrib
, running an hei with 65k coil an msd box to control over rev setting the chip at 5k I won't get an new intake until I get the heads elderbrok has an alum intake to fit the newer vortec heads so from what ur saying I can hit low 200s with the vortecs an intake an cam , the
Cam will match the intakes power 1000-5500

 

One thing you mentioned about asirboats having 400 horses with 4.3 . I have to se it to beleive it.Even if they do they are using a completely different block than what you have.A marine engine which is built way stronger than an automotive engine.Theres a site about building 4.3`s and making big horse power out of them.I dont remember which one or whats it called but google making big horse power from a 4.3 and you will see exactly what your getting into.

 

The 4.3 in a 'yota is a real upgrade for sure, and it fits well.

If you are going to do the work, I'd go with the V8, it will be cheaper to get to 250hp that the 4.3 without a doubt. For 40" tires you should be considering trans, t/c, and axle upgrades for sure. $.02

My old '80 'yota with the stock rebuild 350 was a hoot though.

 

you gotta remember,those boat motors that push a 400hp 4.3..probably has a few grand in the motor. You said u had little money for this.

 

They probally do have tons of cash in them but I'm just saying there capable of those numbers . Buninthink with the vortecs heads a cam an alum intake an1.6'rockers I should be happy

 

You want to get a little more umph from your heads get them ported and polished.

 

Porting an polishing that's a good chunk of change to have done I don't feel good doing it my self

 

I have done it myself I bought or had some some junk heads to pratice on before hand.You can buy the bits for up right grinder pretty cheap online.Its realy not that hard to do just go slow,take your time and have steady hand.I was reading some hotrodders online forum and it showed exactly how to do it.