What would be the biggest cam I could throw at this thing and still be able to tune the TPI setup? I was thinking of something like the CC306 or GM847, but those might be a little big. The heads are getting ported by Lloyd and I will have full exhaust. I'm sure I will need to get a high stall TQ converter too. I'm a LT1 guy so this TPI stuff is all new to me. This is going in a 87 Corvette if that matters.

 

Whether or not the computer can handle it is only part of the issue. The TPI is a midrange performer that's got absolutely NO high rpm ability. Likewise, the stock L98 heads are small port heads that have lousy high lift flow. In other words, a real big cam will not work well on TPI, even if the heads have been fooled with. You need a cam with modest lift, a wide LSA, and a steep profile to get those valves opened and closed quickly to help magnify the reversion effect that helps TPI make all of it's power.

 

oh I see. Well I wonder what the max HP would be from a fully ported set of L98 heads and a cam to match. 350rwhp? I was hoping for more in the 400 range but that might be very difficult with the TPI setup from what it sounds like.

 

Some people would suggest that it's a LOW to midrange set up. I too, would warn against going over board on the cam., especially if your going to keep the stock TPI. Is Lloyd going to install over size valves? What is he match porting the intakes to, stock TPI base?
I did this to my 87 Vette. but went with the Superram, and over size intake and exhaust valves. You'll also need to increase the injectors size, get an adjustable pressure regulator, and high output fuel pump. I uses the LT4 hot cam and was quite pleased with the hp and drivability. I'm sure you could go a bit bigger on the cam depending on what else you've done. Oh, and don't forget the aftermarket PCM tune.

 

What kind of #'s did you put down with that?

Yes Lloyd is doing bigger valves and port matching to the stock TPI intake. I want to keep the stock TPI and I will definently get the fuel end upgraded for sure. I guess I will let Lloyd come up with a custom grind cam and go that route. He seems to have his stuff together on the LT1's, so hopefully we can make some good #'s on the TPI setup. I know it will be nothing close to an LT1 with his LE3 setup.

 

I would suggest giving SLP a call for thei Siamesed runners that are Slighly shorter. The port match the Plenum and Base to match. This will allow you to roll up to about 5200RPM, then start thinking Long Duration Cams with a steep profile and modest lift. Couple it with some 1.6 Roller Rockers and some Long Tube Headers.
Forget you HP numbers out of an L98. It just doesnt get the RPMs high enough to make big Horsepower numbers. Set your GOal to get 500lb-ft of Torque at the rear Wheels. That is doable on a stock shortblock.

 

The biggest cam I have seen with stock TPI runners was with a 230XFI cam. The car made 331 rwhp and the torque was like 380rwtq. The motor had AFR 190 heads. The transmission was a 700R4. The owner is going to upgrade the intake system. I'm waiting to see what he comes up with.

 

my friend put a 250 dur @.050 solid lifter cam on a car with stock somg haeds and stock tpi... biggest mistake ever.... put somehjitng liek a hot cam in it if you are keeping the LTR setup... i would say ditch it and go to something like a holley steath ram or mini ram....

 

Iused the SLP TPI Cam with their runners and had power up to 5200 RPM and didnt really fall off until 5500. Just an FYI

 

MAF won't support much over 350hp

 

Power & performance magazine (winter 2005)used a Comp XR 280 Xtreme st. roller with the following specs. www.powerandperformancenews.com

int. 280 240 .538 110 lobe seperation
exh. 288 248 .538 W/1.6 rock.

I'm using the Hot cam W/1.6 rock. which is:
int. 279 218 .525 112 lobe sep.
exh 287 228 .525

The Comp cam made 5 more torque than the Hot cam and 19 more H.P. Click on the link, click the magazine, then look for PROJECT HUMBLE.

 

Here's the rest. We started with a ZZ4 short block, so I had a little more compression, put a high flow filter and housing on, put a smooth tube between the MAF and the TB, used a 58mm TB, a DUI distributor, MSD wires, Borla CAT back, Y-pipe, and high flow CAT. Topped it off with GM's high performance 4L60 with their 2200 to 2400rpm stall converter.
The numbers don't sound all that impressive 301rwhp, but this is without headers. But the difference in drivability was like night and day. Before the work I could spin the rears from a dead start but that was about it. After, it was so squirrely you had to short shift first and it would burn second and chirp third. Unfortunately I sold it immediately after completion, so no 1/4m times. I was very happy with the results. Good luck.

 

ditch all the tpi junk and get a set of vortec heads and holley stealthram, or an LT1 intake converted for use on a sbc. cc306 cam should be ok then.
you dont wanna throw that much money at something and it still be a turd.

 

where did people get the idea that Vortec heads are so great?

they are a really good FACTORY head
but for the cost of them, or a set of used 1's and having them rebuilt, for another couple hundred, you could be into a set of edelbrock aluminums complete
and you don't have to buy an aftermarket intake,

also TPI is a great intake not a thing wrong with it,
but you got to build your car right if you plan on using it

500 LB Ft of torque at 2100rpm and 350hp at 3500rpm at the wheels doesn't sound fun to you?
put the right cam in and a set of long gears, 3.08's or something
you'd swear you got a big block under the hood,

its all about designing the motor right so many people just throw big parts at cars,
your average head won't flow a monster cam, so why stick it in the motor

if you gave the average person 350 rwhp and 500 rwtq they'd be unbelivably happy

 

unless your building a truck motor, ditch the tpi intake.
i wasnt saying vortecs are all that great, but you can pick them up CHEAP, and they are worlds better than any TPI heads. you can pick up a set of vortecs with low miles for 200 bucks or less. a new set of edelbrocks are up towards $1,000 or more.

tpi stuff = good for a truck motor

what does it usually take for a TPI motor to run 11.70's like this STOCK LT1 motor is?
http://webpages.charter.net/bigjermes/Shonscar_0001.wmv