plentum porting

[chook231]

basically you mean port matching the intake runners to the head? this is common. that is probably 20hp on there 4.2 stroker which i bet had a bigger cam in it also and probably a really good tune. i recon you wouldn't see even half of that on a near stock engine. tack welding extensions into the runners would be very dificult and time consuming as you would need to make sure there sealed properly to the original base. i'd maybe suggest using a product like "knead-it" it sets as hard as metal alsmost and you could form it into the shape you like and then leave it to set. and if it doesn't work out as you though it would require a lot less effort to remove it. using this technique i guess you could get maybe another 1" to 1 1/2" off runner legth. another thing to maybe consider is trying to increase the volume of the intake manifold?

Hey immortality,
you do make a good point there, and yes it was on one of come's mega dollar 4.3 ltr engines with a cam and their sissy tuning, and knead it would probably work better than tack welding, just passing on information that has been passed to me and has by word of mouth worked pretty good.

cheers Tim.

 

[Immortality]

true, but for most that doen't have a workshop avail, getting things welded would be a costly exercise. i'm thinking of trying the "knead it" technigue on the missus VS but it's fairly much stock and i have no way of tuning it without paying someone which i'm not goingto be doing any time soon so i don't see much to be gained there at the mo. places like COME tend to do really good tunes on in house built engines that they show case but when they do a tune that will be sold with something like there stroker kit it is actually "detuned" because of the many variables that are out of there hands when people use there kits otherwise if it was a reallyhot tune and someone put to much compression in there engine it would detonate itself to death and they don't want a bad rap.

 

[chook231]

Hey immortality,
with your come racing tuning theory you are spot on the money with their in house built engines and not wanting a bad rap from something that is out of their control.

With welding the plenum, they may not do it , as the welder who does my jobs would nt weld up the breather hole (22mm)in a set of vn alloy rocker covers as the alloy is to thin and would distort or burn. - so the knead it solution sounds like a good idea , or you could use hi-temp silicone (was succesful in the build of a mild ford 289),or gasket goo would probably work better.

Extending the runners will probably only result in more torque(not dyno kw's) and a better 1/4 mile time.

cheers
Tim

 

[1991_Vn2nV]

Since when does COME have a 4.3 litre kit

Its a 4.2L unless im very mistaken.

 

[Immortality]

Extending the runners will probably only result in more torque(not dyno kw's) and a better 1/4 mile time.

cheers
Tim

i wonder if it would make any difference without it being retuned. last i checked it was a 4.2 stroker from COME. i believe the bradley stroker is 4.3 but i've heard it's weak

 

[IBLOWN]

Do what i did and die grind with a polishing wheel (flap wheel) on the inner plenum until smooth and matchport.

 

[Michelson4301]

Remove the plenum chamber and refit the lid. Hold the plenum up to the sun with the runner inlets facing upward then look through the intake where the T/B bolts on. It's a tad on the small side aye. I ported this section out and with the standard throttle body i noticed a definate increase in accelaration, not bad for $2 of threebond and 2hrs of my time.