Intake/Throttle body question

[ws6drbob]

I was wondering if there were any negative effects from porting my intake manifold to accept a 58mm throttle body while still keeping the stock heads and intake manifold ports unported.

[Al 96 Ram Air T/A]

Negative...no. But positive...no. Unless your running a stroked motor, supercharger, or race-ported heads, there's nothing to be gained by using a 58-mm throttle body. The stock 48-mm is good for plenty of horspeower gains.


Why so big?

[ws6drbob]

Well I have decided on doing heads and a cam but read that I would need LT headers (Ordering in two weeks), bigger injectors, PCM tune, and a 58 mm TB (I will have the Intake ported once I acquire the heads) to see the full benefit from the heads and cam. But I was just wondering if for some reason if I were to put the TB on before the other mods if it would have any negative effects. I will most likely wait until I have acquired everything before I install them though.

[lavapearl]

Boring your intake too a 58mm worth the $$$

I was told by a performance parts dealer X drag racer that the amount of money you will spend to have your intake too 58mm would be around $500 for labor at the machine shop and installation for a gain of maybe 4 HP.Is it worth it,well I plan on doing it some day,every bit helps.

[Z Ya Later]

Save the porting for when you port everything else. Most machine shops will throw it in for a small price. As for putting the 58mm TB on this early, I wouldn't. The gain will be negligible at best and not worth the effort. If you have the TB already, just hang on to it. If not, then don't bother pulling the intake, having the TB bores ported, putting back on then pulling it again later.

[fastTa]

There won't be any negative effects due to the fact that you have a M6. On automatics it could cause a problem.

But I agree with Steve, just wait until you pull everything else, then have the throttle bores opened.

[Injuneer]

I was told by a performance parts dealer X drag racer that the amount of money you will spend to have your intake too 58mm would be around $500 for labor at the machine shop and installation for a gain of maybe 4 HP.Is it worth it,well I plan on doing it some day,every bit helps.

Your "parts dealer X drag racer" hasn't the slightest idea what he's talking about. You can do it yourself with a die grinder. I paid the shop that ported my LT4 intake $50 extra for enlarging the two 52mm holes to 58mm. 58mm is a pretty good idea if you plan to take it over 450-500 flywheel HP, as many of us have.

[Kevin - Blown 95 TA]

Your "parts dealer X drag racer" hasn't the slightest idea what he's talking about. You can do it yourself with a die grinder. I paid the shop that ported my LT4 intake $50 extra for enlarging the two 52mm holes to 58mm. 58mm is a pretty good idea if you plan to take it over 450-500 flywheel HP, as many of us have.

Yep, if it's off the car, it takes about 1/2 hour to mark it and make the holes larger. Maybe the builder was talking about porting the whole thing and matching the gaskets or head ports. Still $500 seems high for that IMO.

[Injuneer]

Actually, he should know exactly how much it costs, because he has a 58mm TB in his signature

[Kevin - Blown 95 TA]

That $500 must include the cost of RRing the manifold off the car as well as the porting job. Still high.

[fastTa]

I bought my LT4 intake manifold from Combination Motorsports. I paid $450 for it, and that included it being port matched to my fully ported LT4 heads, having the throttle bores opened to 58mm, and having the common spots in the interior of the plenum cleaned up as well.

Lavapearl is "planning on" getting his throttle bores opened up to 58mm yet he already has the 58mm BBK bolted on.....OK