chevyguy1969

iTrader: (7)

I am about to start a 355 engine build up for my car have been exploring head options. I have a 350 TPI right now that is getting very tired and want to start fresh. I was wondering if I kept my stock TPI system and went with some aluminum L98 vette heads, a LT4 Hot Cam, 1.6 RR's, and possibly bigger injectors and/or larger throttle body, would I be able to make 300HP or more. I am thinking I might need to port and polish the L98 heads but comparing the cost of going Vortec with the intake needed and getting the heads prepped correctly, im kinda confused on what to put my money into. Anyone have any ideas? The foundation for my build up is a 4 bolt main block, 9.5:1 hyperneutetic pistons, balanced 350 crank, etc. Basically I am trying to get into the 300+HP range on a budget and keeping the TPI system. Something else I was concerned with, what is the max HP a stock torque converter can handle?

8Mike9

If you go with the Vortecs, you kinda blow the budget since you'll have to pop for another $400.00 for the TPI Vortec base.

chevyguy1969

iTrader: (7)

That was my thoughts exactly Mike, $400 for an intake is alot! $400 would make a nice payment towards some really nice other engine parts or suspension parts. Too much for an intake, atleast for me.

five7kid

iTrader: (14)

Stock TPI and Hot Cam is a very bad combination. You'll bring out the worst in both.

You aren't going to scare a stock TC with 300 hp. Stall speed is the more important question.

chevyguy1969

iTrader: (7)

Hey Five, i would like to know more about your thoughts on the stock TPI and Hot Cam being a bad choice. I dont mean to slam you or anything but... On SDPC's site when they tested their Vortec intake they the Vortec heads of course, a stock TPI system, LT4 Hot Cam Kit with 1.6 RR's, headers, and all emissions devices hooked and made NO changes to the computer and pulled like 320HP. How can that be bad? That exactly what I want to do and at the way things are going, just might do it since it is kinda proven.

Also, what stall speed would you recommend?

five7kid

iTrader: (14)

How "stock" was that TPI? CHP magazine used aftermarket runners with that base to get their power numbers. Also, there's a big difference between dyno peak HP & torque and driving in the real world. I wouldn't use the word "proven" with a combo that spent a couple of hours on the dyno (at most), with a high lift cam and press-in studs.

I'm trying to remember his user name, haven't seen him post for awhile, but a guy out here tried the TPI/Hot Cam/1.6 rocker combo on his 350 (not Vortec), and he slowed down.

I'd guess you should go at least 2000 stall with that cam. Mine feels real nice with the 2300.

E-Z Rollin

Yes the alum.chevy heads will defintely make over 300hp stock and more if you port them,I suggest a pocket port which you can do youself. David Vizard's, Max Performance Chevy small blocks gives info. to port those exact heads. As to how much cam is compatable with your tpi,get your info. from someone that has actually tried that cam with tpi,you'll get more accurate info.

Grim Reaper

I have to agree with 5.7. I too have the magazine article and Test 3 is not "LT4 Hot Cam Kit ONLY". They also used Edelbrock runners and TB (52 mm I suspect), plus the LT4 valve springs were added in Test 2 for the ZZ4 cam.

To be completely comparable they should have used the stock runners and TB, but I suspect the results would have been numbers much closer to the Test 2 and that is why they added runners and a bigger TB - because the LT4 Hot Cam was chocking for lack of air.

Also, they only took the dyno to 4,400 rpm. I suspect that is no accident either, as it would have shown a sharp drop starting at 5,000 rpm.

My feelings that the LT4 Hot Cam wants a lot more air. I wonder what the results would be if they had tested a Miniram III (Vortec port version). I think you would have seen an engine that produced a flater TQ line who's peak wasn't that much worst, but made great HP up to 6,000-6,500 rpm that would have made the other 3 look sick.

Now add up the cost difference between Vortec TPI Manifold and Runners vs a Miniram. You can ignore the rest because you'd have to change all of those anyway for either setup. And that includes the eprom. The only assumption I would make there, is that you'd go to Ed Wright or Jim Formato (his company, Jim died a couple of years ago) and they'd charge the same for the setup for Test 3 or Test 3 with a Miniram.

I bet the difference in HP for the extra cost to "upgrade" to a Miniram would be your best "HP/$" bang.

jmon92conv

just wondering, but what if you dropped it down to 1.5's on the hot cam?

Jeremy