I'm doing heads and cam (230/236) soon. I may upgrade to a larger throttle body after the heads/cam are done. I want to port the intake for this while I have it off the car. With out the specific t.b. gasket I dont have a guide. The thought occured to port the intake in a larger rectangle similar to the way a single plane carburated intake is. Dont know if that would create another problem though, then again it might provide better flow to the intake plennum and better throttle response. If I picked a specific brand and size throttle body is there somewhere I could download a gasket pattern or is there just no safe way to do this without having the t.b. and gasket in hand?

 

I have read that there is a problem with porting the intake when you don't have the throttle body and gasket in hand.

My understanding is that not all throttle bodies are created equal, like AS&M TBs the ports are spaced differently than on the Holley, etc...

So you really need the gasket for the brand and model of TB you plan to use before you port it.

As for a single larger port, I have no idea.

 

Yeah, I know for a fact some t.b.'s are different from others, thats why you need the gasket for a guide.

Anybody else have an opinion about one large rectangular opening?
How would this affect flo?

 

I'm not sure how things would be affected, I know you will get alot more air flowing through the LT1 intake, but was the LT1 intake designed for that much air flow. I would say go with an Lt4 air intake, I know the raised runner is made to flow alot of air and increase the port velocity. I may be wrong, but this is good question and worth some research on the LT1 intake.

 

Well it will still flow though the throttle body first but it may be less restrictive from the throttle body to the intake plenum. Perhaps that peice of material on the intake is acting like a restrictor plate.
Single plane intakes usually have relatively short runners and equal size venturies on the t.b./carb like the LT1. Dual plane intakes have unequal length runners and unequal size venturies like a quadrajet for example.

 

How 'bout the evening crew, anybody have thought about this?

 

If you cut a large hole, your going to cut into the IAC hole in the intake, which is not good. Most throttle bodies are set up "0" except for the AS&M ones. The only ones that are offset on theirs is the 54mm from my knowledge.
If your just going cam and stuff, you won't need more than a 52mm which won't even require doing anything to the intake.

Also, save your money, the lt-4 intake isn't worth the time. (You do have to have the lt-4 heads ya know)

-Shannon

 

OK thats what I didn't know- that it may interfere with the IAC which has a separate hole. I never said anything 'bout the LT4 intake, I'll just have my LT1 heads ported. However, I thought a 58mm would do that set up (XE230/236, ported heads- intake flow 280 @ .600) some good.

 

I was referring to the post about buying an lt-4 intake If you pull the TB off, you can see how the intake has the IAC hole going into the intake.

Try this link out for a 58mm TB

-Shannon