I will be getting a stock TPI intake in the mail soon and the reason I got it was for it to go with my fully ported & polished stock 305 head project.

I decided to go ahead & fully port and polish the TPI intake first, then put it on my existing TPI setup with my normal heads to see how much of a gain I will get just off of the intake.

I know there is nothing to port on the stock intake but I will be widening the intake to head ports a bit, then taking all of the inner casting off with a die grinder, then polishing it to a shine since there is no need for texture in the intake manifold since the injectors end up right in front of the heads intake runner anyways.

I know this will be very good for air flow, but just how much more of a gain am I seeing here, to compliment the new intake I am going to open up my siamesed runners on the plenum side a bit more.

Has anyone ported & polished thier stock intake? And if so how much of a gain did ya see by doing it???

I don't care if I only gain a tenth, every tenth counts. I want to see how far I can take my stock L98 cam and TPI setup.

what do you guys think? is it a waist of time or worth the effort?

p.s. I know aftermarket intakes are the way to go, but seeing as how I have a 305 and not a 350 there is no need to spend an extra 500 bucks on one if I'm not getting a big lumpy cam any time soon.

any opinion, negative or positive are welcome.

 

There's room for improvement on the stock intake, just not as much as in an aftermarket one. Polishing will be a waste of time, you wont gain any more flow from it. The only thing to do is to smooth out really obvious casting flaws. You could try siamesing it also.

 

i'd rather not siamese a tpi intake for a 305.


thanks for your opinion.

 

Well to be fair, you did ask specifically what everything you could do to the stock TPI would be... I'm afraid you're just about done then if you're not looking to siamese the base. You have the plenum work done, you have siamesed style runners, and the next step is the base. Mind if I ask why? It will show you some gains and you did say "every tenth counts".

 

I don't have a 350 therefore there's no point in siameseing my intake, I would lose to much torque by doing it.

I'll just go deeper with the siamsed runners & shorten the runner length even more, that will pretty much do me about the same.

Every tenth does count, especially when using stock equipment, but then again you don't want to over do it & run a tenth slower right?

 

Then you should learn how to burn your own eproms and tune it. You may find more than a "couple of tenths", not to mention better driveabilty and improved gas mileage.

 

I am already getting into prom burning, I have a laptop running craig Moates software, craig moates adaptor, a few flash proms and steve ruses adaptor cable, I'm all set on that side of the field, all I need left is a power programmer.

thanks for trying ot help me out though

 

You may be better off trading in some of that torque for more horsepower

 

LOL, thats what the runners are for.

I have not touched the runners since I got them, only rmoved soem of the casting tomorrow I am going to re port them & make the siamsesed part way wider.

 

wait, siamese the intake? hows that done?

I just got my TPI stuff, im putting together my first TPI motor here in a week or 2. Its going on a 355 with an XE262 and perf. RPM heads. I would like to dump some of that torque for horsepower too...

the runners intake and plenum are all untouched. I was going to smooth out the factory casting with a carbide bit and a die grinder, then buff it a little with sand paper to smooth it out. Is there any place to actually CUT the thing to reduce runner volume or length or what not. is that what siamesing the intake is? can somone explain what would be the best way to set this thing up? I dont want aftermarket runners yet, until i learn to tune the stock setup and all that good stuff. i just want to add that fuel economy is one of my primary concerns, thats why im trading off this carb and blower for a stock Tpi setup.

 

Excellent.

 

Siameseing the TPI intake frees up a lot of resriction on a 350, by removing the dividing runner walls about 2 inches in +.
Here is a picture of an EXTREME siamesing



That is obviously more than 2 inches deep lol. About 5 inches, but you get the picture.

 

SHould i do that? Will it hurt my fuel economy or drivability much?

 

if you can't burn proms YES.