after a while of researching I started building a 383 I was wondering what kind of hp to expect from this I know the tpi will choke the engine what can I do to help this?

useing the following

pro top line torqer 202/160 heads
srp forged dish 9:8:1 compression
roller cam 210/215 462/470
slp headers w/air tubes 1-5/8

the buttom end is all useing forged parts for a large nos shot

my goal is 350hp 400 or so pounds of torque while staying smog legal

 

The stock TPI will choke up that 383cid...

If u wanna take max advantage of that block, I'd suggest a super / stealth / mini ram setup, but I understand those are pricey.. so if your going to work with the stock setup, let's see..

-SLP Hi-Flo Runners + Baseplate
-Ported Plenum
-52mm Throttle Body
-#22-#28 Fuel Injectors
-Aftermarket AFPR

All of that will add up to over 1/2 the cost of an aftermarket TPI system (super / stealth / mini rams), so u may just wanna save up some money instead of going 1/2 way..

Just some thoughts

-LJ

 

yeah I want to stay with the stock tpi system. would thos mods get me to my desired hp/torque range?

 

youll get more torque then that...more like 450+
but itll struggle for HP

what u could do is go over to www.LT1intake.com and talk to john, he posts here often to so get a hold of him..

he converts LT1 intakes to work with SBC heads, it a great deal..

that is basically like a mini ram but a whole lot cheaper..

 

problem with that system is it doesn't have a egr valve. this engine is already going to have problems passing emmisions I don't want to press my luck

 

if your in good tune and have cats then youll pass with out an egr

that cam isnt to bad...ive seen bigger cams pass

 

Would a RAM AIR II hood (WS6 Style) with a K&N ram air box help out at all?

 

wouldn't this function like ram air on a new trans am? 20hp or so at high speed?

 

ok still deciding on what i'm going to do. I found a superram on jegs for around 780 or so. how much better would a superram flow then a tpi with a 58mm throtle body larger runners and a ported base?
ok better example say the engine puts out 300hp with the tpi how much would it put out with the superram?

 

I have a 383 with AFR heads, ZZ9 cam, headers and Superram base.
I was running the stock TB, plenum and runners and was putting out about 355HP and 460FT-LBS (at the crank).
I have since added the Superram plenum and runners but have not dynoed it since I am also waiting to put on the 58mm TB. The addition of the Superram plenum and runners has made a noticeable difference though.

 

The entire Superram set up would make alot more power than the stock tpi however the one you saw on jegs is just the plenum and runner kit for about $780. but you would want the superram baseplate or manifold I would think before the plenum/runner kit. Since the stock base will totally restrict the flow of it. Either way, even if you built this engine and ran the stock TPI set up I dont think you would be dissapointed with the results and you could always upgrade the intake later. That is what I did with my 400. I would say if you havent bought the cam that you mentioned to go with one with more duration though, as long as you didnt go to crazy emissions wont be a problem. Also wanted to mention that some of the Pro Topline heads do not have EGR provisions either.
Good Luck!

 

how big of a cam can I go I was already told this is about the biggest the computer will take, I was told anything with more duration would give me emissions problems? this is already a little bigger then a lt4 cam

 

Regarding emissions, my car passed NY emissions less than halfway up the limits for everything with no egr, no air injection, yes cats, and the ZZ-409 cam w/1.6 rockers(226* @.050 and .555 lift). As far as hp on a 383, I'm still tuning mine but with the above cam, AFR heads, and TPIS base, runners, ported plenum, and 52mm tb it made 315 rwhp and 405 rwtq running too rich. So if you're looking for 350hp at the crank with a LTR intake it is definitely possible, although maybe not with stock intake parts.

 

I guess where you live and the emission guidelines would have alot to do with how much duration you can get by with. The thing is about a stroked engine 383-400+ cubes is with the longer stroke they seem to be able to get away with using longer duration cams and not screwing up the computer as they maintain good vacuum #s. However I didnt see anywhere in your posts if you had a Speed Density or a MAF system. If you have SD it sounds like you are going to have computer issues reguardless. I use MAF and where I live in CA, I think the emissions testing is pretty much as strict as it can get. When I first put my 400 together (9.5-1 compression using a fully ported stock TPI, fuel pressure @50 psi and a 214 in. 224 ex. @.050 with 112 lobe sep. cam), It flew through the smog test. I didnt want to fail and I knew I was going to change the cam anyway, so I was pretty conservative with the cam first used. There are guys running the LT4 hotcam in 350s and passing smog out here (218 in. 228 ex.) I am in the process of changing my cam now to a 222 in. 226 ex. with 114 lobe sep. I am pretty confident it will not be a problem passing again.

 

er I think it's sd how do you check for sure? this is really turning out to be a pain in the *** I hate computers. what do I have to get done if it's sd?

 

What year is your car? 89 and earlier was MAF, 90-92 was SD

 

it's a 1987 so it's maf? do I have to do anything with it?

 

so that lt1 intake for 400$ will work with a TPI computer?

 

StealthElephant

Any intake will work with stock computer as long as you burn a custom EPROM for it. The stock fuel tables are designed for the low rpm TPI setup and a miniram, stealthram, superram, lt1 setup will be very lean up in the rpm band north of 4000rpm. Plus the stock spark advance table just plain sucks.

 

i'm going to just upgrade the stock tpi setup, what runners do you reccamend accel runners or slp? I heard slp isn't a direct bolt on?
I was going to buy the elderbrock highflow tpi baeplate and the accel high flow runners and have the plenum ported?
and get a 58mm throttle body

 

As long as you match everything right and do some PROM work, you should be fine with the TPI. It will have good HP and incredible TQ with what you want as the others have said.

 

well depends on what you call good hp, I wish I didn't have to take emissions. I would of thrown the tpi out and put a holley carb on it and would have probly been making 400hp