I am debating on an Converted LT1 intake swap. iv got a 400 w/ edelbrock RPM heads, crane 2050compu cam. (454/480, 216/228) with 1.6 rockers. about 9.5:1 1 5/8th headers i dont want to rev the motor over 5500. what kind of performance gains would i get over a stock TPI unit compaired to the LT1 setup? iv got a 5-speed w/ a posi and 4.11's and i want to run 12's. emissions really isnt a problem. do you think the LT1 intake is good for me?

 

What are the specs of the heads? Sounds a little mismatched. The LT1 comes alive at 5500 rpm. Also if you went with the LT1 i would suggest a bigger cam. I think a super ram or stealth ram would be better for you.
JP

 

170cc intake runners 70cc CC's 2.02 1.60 valves......

 

what would the difference be from running the stock TPI (exept 24lb. injectors) be over running an aftermarket intake? i know its a stupid question but my father seems to beleive ill run really good and the car will be a monster with the Stock TPI on it.....

 

That thing will be a torque monster the way it is now. Thats not a bad thing, i happen to own a 406 TPI in my jeep. It depends what you want to do with the car. The only thing out of place if you go with TPI is the 4.11 ratio. TPI especially in a 400 won't rev real high, so the 4.11s will keep it in the higher rpms where it doesn't make power. I would suggest 3.42/3.45s If you can get the 400 TPI to hook up it will smash you into the seat every time.
JP

 

Bone stock TPI on my car will probably produce ALL its hp and torque under 4500 right? well i was thinking either 3.73's or 3.42's cause i wont be reving that high....but im living with my father and he always "suggests" things and if i dont go by what he says he decides to yell at me and not help me....so its pretty much his car. lol but im not 100% sure on what series carrier i have. but i dont know i should be able to put 373 on it. my mothers vette has 3.55's and that thing goes pretty good on top end(78 w/ th350) i just want more higher end power and i know the stock TPI wont let me go high. i want to be able to do a little road racing up to about 130, beleive it or not iv had the car up to 138-140 with the "stock" 305 i think somethings done to it cause it goes pretty good for an old LG4. there was already a 160* thermostat in it and now i changed it out and it spark knocks more, either the timing is advanced or theres an aftermarket chip in it but i swapped in a 140mph gauge cluster but anyways i want to be able to burry the needle. and with 4.11's i dont think i can without extrem high rpm's...... what do you have done to your 400 and what are you running?

 

My 400 is in my jeep for offroading and rockclimbing. It doesn't see over 3000rpm often it runs high 12s though. Its a 400 .030" over.
steel crank, ported L98 aluminum heads, ported TPI, LT4 Hot Cam

 

i want to see how much the LT1 makes ont hat 350 but if it doesnt help me with my cause then i dunno.......

 

i dont know about it coming alive at 5500 RPM's... my 93 LT1 camaro sure didn't! it started falling off around 5800, and it was about done at 6000... this was all stock though just a chip (with raised rev limiter in case you were wondering), i agree that the stealth ram would be better, powerwise at least, but i think the LT1 intake will do great still especially if it doesn't go over 5500, and the LT1 is a little cheaper, i think www.lt1intake.com sells em for like $450 or something, and the HSR is around $600, the super ram is way over priced IMO, and so i dont consider it an option, one thing to take into consideration though is that the HSR has no EGR for emissions, does the LT1? read the "ram that TPI" articles in GMHTP (it in the last 3-4 issues) they put the HSR on a camaro that was modified (heads, cam TB, headers, 355, etc) the car already had ported base, with slp runners, and the HSR still picked up over half a second if i remember right, and they discuss how the TPI is done making power around 5500 RPMs (thats on a 350, your 400 will be closer to 4500 or so) and that the HSR is sooo much better basically, have your dad read these, it might help persuede him


BTW john millican (lt1intake.com) is in the process of finding out how much RWHP is gained by doing the swap on a stock 350 TPI, so if you can wait a month or two he might have some dyno #'s for you

 

also that 400 is gonna KILL your T-5... GM didn't put the T-5 behind stock 350's because they weren't reliable enough

 

I think the LT1 will be perfect, low priced, good performance gain on more modified engines, i have a tech article with the TPIS intake that has the intake the same exact style as the LT1 intake, and it made 34hp over a stock type setup. and it made a more smooth torque curve instead of more low end torque, i can scan the pics of the charts and post them, its got 10 different intakes all tested on a 350...... it has TPIS Holley projection cutler/haltech street and performance, arizona speed and marine(which performed the BEST) i can post all the dyno numbers if you want for them but they also tested it with an RPM intake and 750 holley vacum secondary carb. let me know if you want me to post all these numbers, its very interesting how they turned out.

 

yeah well i just figured my first few runs down the track i might give the officials something to do....as in.....picking T-5 peices off the ground.....lol....well i hope that doesnt happen since the nearest track is in canada.....and thats where i go to race....if i had the money id make a drag strip right here by my house, id absolutely love it! but later on ill see if i can upgrade to something other than the T-5, or do they sell kits to upgrade your tranny, im not sure on the Exact weak point of the tranny's but they must make beefier parts for them..... ill have to do a search on it....and ill give the numbers and what the intakes were and what the motor is here......

Ok first of all its a 350cid with a performer RPM Cam(488/510) dur? i think its between 230-240. it has crower sportsman rods. B+M water pump and pulleys. MSD wires, HEI distributor accell plugs and held together with a complete ARP bolt set. and finally hedman 1 5/8 primary headers.

1 Edelbrock performer RPM intake w/ Holley 750CFM vacuum secondary carb. - 322.8hp@5250rpm 353.0tq@4500rpm

2Holley Pro-jection4- 332.6hp@5000 366.9tq@4500

3Fuel injection specialties(stock) 294.1hp@4500rpm 366.0tq@3500rpm

4 Street & Performance(basically stock w/chip) 308.6hp@4500rpm 376.9tq@4000rpm

5Arizona Speed & Marine 328.3hp@4500rpm 402.7tq@4000rpm

6Cutler/haltech efi 336.3hp@5350rpm 358.3tq@4500rpm

7Tuned Port Induction Specialties(TPIS) 328.3hp@5250 355.0tq@4500

8 Accel Injection(1000cfm huge intake) 317.9hp@4500rpm 378.2tq@ 4000rpm

9Electromotive 301.6hp@4500rpm 392.5tq@4000rpm

i didnt list one because its BDS and i dont think its even produced anymore(magazine is 1992)i can show the dyno's on all of them and it shows a comparison to the carb. in my opinion the best would be the Arizona speed and marine, it made over 400lbs. of torque and the hp wasnt far off the highest ..... you also have to take in mind that the cam that was in this motor has higher duration than a normal TPI based engine would have....but it might not effect some of the other styles i dont know, someone would have to correct me on that i guess.....but the TPIS looks just like the LT1 and it made 34hp more than the regular TPI did.... but it made 11 less torque also these tests are all on an Engine dyno not a chassis dyno. with a basically stock 350 with an RPM Cam and the cam is also "matched" so edelbrock says, to there intake, so maybe thats why the RPM setup got the benifit over the TPI applications. but who knows.... i wonder if any of this info helps anyone out? its basically stock maybe john could go by this if the TPIS unit is like the regular LT1.....

 

I'm talking about a properly built engine not a stocker with that wussy LT1 cam. That cam is only slightly bigger than the L98 and the L98 is only disigned to rev to 5000rpm. The LT1 can take you well over 6000rpm.
JP