Okay, I have a decision to make. I recently won some stuff off ebay which included a ported plenum, ported and siamesed SLP runners and a ported stock base. My plan was to sell the base and go with a TPIS unit, but after recieving the parts I was so impressed by the port work done on everything that I'm wondering if it would even be worth it. I know I have read that a fully ported stock base will still not flow what a TPIS unit can, but how much are we talking about here? This sucker is hogged out, the runner ports match the SLPs and it looks like work was done throughout the entire runner length in the manifold. My combo will consist of a 383 with AFR 180cc heads, 224/230 camshaft with .510 lift, and I'm shooting for the 450hp mark. If I'm leaving 10-20hp on the table using this base I can live with that, but 40-50 obviously I'll go with a TPIS. Any advice?

 

Post up some pics. I just installed my ported base can't wait to see what that does.

 

450hp out of a TPI 383 is askin alot.... i dont think a port stock base will get you there, nor will that cam or TPI in general. you should be over 400hp but not 450. i'd step up to a slightly bigger cam to go with the siamessed slp runners. but a ported aftermarket base probly will be best

 

I won't be heartbroken if i don't hit 450 on the mark. Any dynoing done would be on a chassis dyno anyways. Not only that but I'm still trying to figure out if I'm going to supercharge it with around 6psi or not. After reading through the infamous TPI shootout article again, the difference between an extrude honed base (which granted mine's not extrude honed but it is nicely ported) and the Big Mouth base was 10hp, and that was with larger port heads and a bigger cam. So I think I'll stick with this base.

Here are some pics of everything:

 

Those look nicely done, I would put them on if it was my car.

Here are some pic's you can use to compare them to my accel base and AS&M SS runners, might help in you decision.

 

runners

 

yeesh, what kind of times are you running with that setup? how much boost are you running? I had a P600b on my car until august when it self-destructed and dumped a ton of debris into my oil pan, hence the rebuild.

Nice setup man. And yeah I think I will stick with what I have, this stuff is nice and I probably will go with boost again anyways.

 

I dont think thats been opened up like you think unless those pics are deceiving me. Looks like it got some minor sand roll treatment to the most restrictive part of the base in the middle, and most of the work at the ends where it meets up to the runner and the head.

A well ported stock base supposingly will flow as much as an unported aftermarket base, if that means anything.

 

ill agree that with that setup it'll be hard but give the tpi more than that.Articles That Use Comp Cams® Products.
451hp with stock base and TPIS runners. they hit 460 with the TPIS base. the deration looks good, but i do think youll need more lift. with the 180s youll make more bottom end than that motor and sould still be breathen' nice up to around 5000. looks like a very nice setup man, major props.

 

just saying that was an awfully big cam to run in a 383 to get to 450hp. that cam would be more suited to a 500hp miniram setup...like shown in the article. that cam didnt come alive till way up in the rpm range.

i think 450hp is asking alot from a 383 and TPI in a streetable car.

 

Thanks for the input, guys. Honestly for what I saved buying this over what I was going to spend on a new base, runners, plenum port etc., I'll most likely go with forced induction. My original goal was over 400hp N/A, which I think I can hit that at least, but hell, why not throw some mild boost at it?

I will admit Madmax I don't know much about porting, other than what the plenum and runners should look like. I figure I'll use this piece and if for some reason it doesn't work out change it down the road.

 

Oh nothing special just a high 12, that's with the 10# pulley. Might be worse now with the extra weight of the new rear but I think I might order up a set of those new AFR heads and see where that takes me. How did you do with your car with the P600b?

BTW beautiful car you have there love the hard top!

 

A ton of port work has been done to that base, the the mid section is enlarged and the restriction where the base turns before entering the heads is now gone. It will flow quite well, probably very close to an aftermarket base. You might want to post some more pics of the ports where they enter the heads.

 

Tony>

My best time was 12.52 @111.1, track temp was 105 degrees and that was with a 1.98 60ft. I was sure I could hit high 11s with much cooler air and some stickies, but I never got the chance Hopefully this time around I'll be there...I figure 12s N/A or high 11s S/C will make me happy.

 

Hmmm seems the P600b is a better match for a stock motor from the ones I have seen your all in the 111-114mph range, what was your boost at say 3500,4000,4500.5000,5500RPM if you can remember?

 

I see parting lines from the casting in the middle areas of the ports so... I dont think much of anything was done there.

 

My heads and intake were completely stock, compression was lowered to 8:1 and, when it was cool, I was hitting 15psi at 6000 RPM. Intake temps made an enormous difference in referenced boost pressure, so I had just put meth injection on the car and was actually testing it out when I grenaded the head unit. I want to say, if I remember, it would hit 5psi immediately when mashing the throttle and then slowly climb, probably 10psi by 4000 RPM or so.

I will say, though, after doing alot of reading and knowing the manners of the car it wasn't an ideal setup. With the 3.70s out back the thing would wind up so fast that just when you were really getting the thrill of acceleration it was done. It would pull really hard to about 4500, then still keep pulling but there was a noticeable drop off, and then shift at 6000 or so. I mean it would rev past 4000 in no time flat. The car was far more impressive on a launch (if you could get it to hook) and 20-40mph roll than it was on the highway, again, because you were almost at 5000 as soon as you nailed the gas.

This time around I'm throwing the stock 3.23s back in, the heads and intake are going to flow much better, etc. etc. So I'm hoping for more useable power down low (less tire spin) and more time in the peak power range (and more peak power). I may also stick with a 355 if I supercharge, for cost reasons and because I'll already have much more torque down low than I'll know what to do with.

 

How did she drive at 8:1 compression? Thinking of ordering up some AFR heads, the 65cc ones will give me about 9:1 and if I go with the 75cc ones would be around 8.1-8.3:1 compression.

 

Never had any detonation issues no matter how much boost I saw. This time, I'd like to run more compression with less boost, put less stress on everything. Using a DCR calculator, with 9.5:1 static and my current cam (comp cams custom s/c grind) I should be able to run 8psi of boost and get the same DCR as I had with 15psi and 8:1. Plus switching to aluminum heads should help also and I could probably push it to 9psi.

 

I took a ton of metal out of the midsection of my intake and you could still see parting lines until I media blasted it.