You can see my specs in my info on the side. basically I am either going from tpi to lt1 conversion or to a carb conversion (750 holley vaccum secondaries). what kind of gains do you think i will get and how fast/how much faster should my quarter be? which one would you suggest going for (found an lt1 conversion minus tstat housing and couple other small parts for 500, and i can get a zz1 manifold with the holley and a couple other small parts for it for 225) thanks a lot.

 

Maybe not a whole lot more peak power, but youll make more power about 4800 rpm where the TPI stops making power. The Carb/LT1 will allow you to rev upwards of 5600k rpm and still make power.

 

if your going for ultimate performance, don't get a vacuum secondary carb, go double pumper.

 

which route would you suggest, or would you suggest something different. if you have an opinion would you please explain, again, if you could help out with some idea of a 1/4 time. thanks a lot.

 

this is my daily driver. i knew i had to do something about the intake though because a stock tpi from a 305 on a high output motor just wasnt cutting it. I think this will top it off for me, at least for a while before i would like to do anything else. money is a factor, as is mpg.

 

Don't go carb if you want MPG then.

 

but the lt1 will cost much more in the long run.

 

the 305 tpi and 350 tpi manifolds are IDENTICLE! put some nice runners on it, big throttle body, port the ever living crap out of it and then learn how to tune! the computer is your weakest link now, not your manifold.

 

What injector size are you running? Isuggest upping to some nice 24#'s. Some SERIOUS tuning is neccesary.

My roommate has a Vacuum Secondary 770 S/A carb on his 383/T56 combo, pulls around 22-26 MPG on the highway and somewhere around 15-20 MPG in city. His car fires on first key anyday and purrs like a kitten.....put down 373HP/401 TQ

 

i am trying to be cost efficient here though. and i have no idea how to tune. im probably runnning stock injectors since the previous owner never said anything about them when i bought the car (and he included a rack of reciepts with it). also i think it would be cheaper (and easier) to just do the carb swap and sell all the tpi stuff. more opinions and explanations would be great. thanks a lot.

 

Going to carb you'll also have issues w/ the fuel pump/pressure, so you'd need a $70 fuel pressure regulator that ends up kinda jury-rigged to work and lower the pressure, or you'd need a mechanical pump to install and drop the gas tank and remove the old pump/put in a standard pickup. Both are kinda a pain in the ***. I ran the Mallory FPR and stock TPI pump for awhile on my TPI-to-Carb car, but my fuel pump died after a year or so and I ended up having to drop the tank and crap and do it right anyway... The whole time I had the carb (it did run good, and was easy enough to tune) I always wanted to convert back to a FI setup (had Vortec heads so I was limited in choices), if a Vortec SteathRam had been available I likely would have tried that...

I think in your case I'd lean toward just getting a better FI intake setup, either a LT1 conversion or since it looks like the one you're pricing is $500ish wouldn't a Holley StealthRam be the same price/cheaper and easier to install?? Get the adjustable FPR StealthRam package and you can at least attempt some rudimentary tuning via the fuel pressure if you're not willing to get into custom prom stuff...

What are the stock cam specs on the ZZZ assuming you still have the stock cam in there?? Only quick search of the net turned up a 235/235 duration at .050 result, that's not right is it?? If so you'll get some pretty huge gains when you go to a shorter runner intake setup better suited to that cam, that can't be even close to ideal for a long runner TPI setup...

 

BIG CONSIDERATION: IM240

Your car will have to pass emissions in MD, and that means on the rollers. Good luck getting it to pass with a carb and no feedback via O2 sensor. I would keep it FI, and lean towards a stealth ram, mini ram, etc instead of an LT1 swap since it already is TPI. You are going to have to do a chip to get it to work right. I would lay out a plan for which intake, other parts, etc. along with the $$ for some tuning software or a hookup to tune it, and double whatever you think it will cost. Save that up and then gitter done!! And don't plan on using it for a little while after you get it back together, it never works out that way. Been there done that. A good intake will wake your car up on the top-end bigtime versus the TPI that is choking it now.

 

Good point, I completely forgot to mention that. Emissions was a headache for me. I was able to get my carbed 350 to pass the IM240 dyno emissions test here in Ga the last couple years w/ the only emissions device being the new catco cat, but I had to detune the car and run it really really lean to do it. I've about convinced myself I may have burned a valve or something the last time I did that, once retuned to normal my engine ran slightly rougher and I was never able to find a cause for it before it was totalled (swapped plug wires/plugs, cap/rotor, etc and came up empty...). Who knows, just a thought.

 

Forgot to ask, how slow is it in the quarter, and what is your goal? If you have timeslips, post all the #'s.

 

Not being a dick.... but stealth ram and mini ram aren't emissions legal are they? Unless MD. emmision laws differ from PA's. PA says you have to have a fuctional EGR valve to pass emmisions.I know Stealth Ram doesn't. I thought basically your only option was super ram.

 

ok first off i just passed emissions a month ago and dont need it done for 2 years. at this time i can get historic plates in a couple months anyways, so im not too worried about that. they dont check under the hood either, just the fumes. about the stealth ram, i have aluminum corvette heads that came on the zzz, so the port is a 1204, so i would have to do port matching on my heads to put the hsr on, which im not really looking forward to doing. that is the correct cam i have 235/235. it came with it and its still there. i just figured out that the lt1 i wanted was made for 1205 heads as well . and the guy whos selling me the intake/carb for 225 is including the fpr in that order along with new jets and some other small things. plus i would not have to port match anything. he is actually selling the original zzz intake manifold that you can no longer buy new. i imagine this manifold is good for this motor if it was built for it. so after all of this, do you guys have different opinions at all. as for my 1/4 times now, i dont know. im guessing 13-13.5

 

MD is don't ask, I won't tell (they don't pop the hood, just look for a cat and check the gas cap). I passed with a 230/236 cam on a 110 CL thanks to my DFI...on the rollers...fast pass. No AIR, no EGR, just a cat and a decent tune.

As far as historic tags, check again. Historic tags still get tested for emissions in MD.

As far as track times, you need to go now and set a baseline, and from there pick a goal. You might be able to do a converter, gears, TPI port job on what you have and achieve what you are looking for while still being smog legal.

 

im not really trying to reach a certain goal. i am just basically trying to see what kinds of gains i can expect from the different types of induction i am choosing between. do street rod tags also need to pass emissions?

 

You can't quantify a gain without a starting point. You need to go down the 1/4 right now as is to get a baseline. Then you mod your engine. Then you go back again. Without "real world" data, you can't tell what your gains are. SOTP doesn't do it, it can feel quicker and be slower.

A different intake will trade off low-mid range torque for top-end power vs the TPI. Whether or not it's quicker down the quarter is dependant on you taking at least 2 trips to the track. You still need a baseline of where you are at, which would require at least one trip to the track.

BTW, emissions in MD goes by the year of the car, period. If you keep it FI you will not have any problems.

 

i guess i can try to get it to a track. anyhow, what about what i said about the hsr not fitting my heads. is this true that it wont work, or will it just not work to its full potential? if not how hard is it to port your heads/how much does it cost to get done? i guess my question at first wasn't really what i was looking for. basically i was saying between the hsr lt1 and carb conversions, which could i expect the most gains out of. and im not about to go out and try all of them. not only which would get me the most power but also which would be the most practical.

 

The regulator the carb intake setup will come w/ will likely not get the job done. You need a specific regulator that can crank the high pressure fuel injection pump down to carb friendly levels, and it needs to be a return style as well. Mallory makes the one that I and a few others around here have used for this for like $70-$75 IIRC (I believe it's the Mallory 4309, can't recall).

Read up on the TPI to carb swap, there are several issues to deal with, it's not a simple swap the intake on 30 minute deal.... You'll have issues w/ mentioned fuel pressure stuff, the torque converter lockup that was previously computer controlled, need to rewire the fuel pump/oil pressure safety setup to get the pump to come on w/o the computer, will need a new non-computer controlled distributor, etc. All this runs the cost/hassle up.

The stock ZZZ intake is probably about equivilent to the standard Edelbrock Performer intake if it's similar to the intakes GM has been putting on the rest of the ZZ series crates. Leaves some room for improvement if so.

Plenty of people are bolting the HSR to stock L98 heads/other 1204 port heads w/o the port matching on the heads... Holley did back when they were first posting the dyno results on a stock 350 TPI around here... However you could do it fairly easily w/ a dremel or similar with the heads still on the engine if you're careful to not get metal filings/shavings all down in the engine...

 

when porting the heads do they need to match absolutely perfectly? or do you just kind of make them a little bigger and smoother to a somewhat accurate size?everybody makes it seem like no big deal. and trust me, i have access to any tool necessary for it at school, but i dont trust myself doing it if it needs to be perfect. but if you are saying that i can in fact bolt the hsr on without port matching with absolutely no problems of any kind cept for restricting what i could be having than i will throw away my other ideas and get it.

 

ok i talked to my friend in class with a couple race cars/funny cars, etc. and he said we could port the heads at his house. i think i will go with the hsr setup. my other friend bought one and decided not to use it, so it is still new in box and he would give it to me for 450 (manifolds with rails and afpr). you think i should grab this and do it?

 

also, when i do it, how can i use the afpr to tune it? what should i look for and what should i do to adjust what is wrong?

 

I've read 3 articles on the HSR on a stock tpi engines all of them show about 30-35hp gains over the tpi and about .25 off the 1/4 time. Its a excellent upgrade I paid $528 w/ fuel rails and adj fr shipped to my door from summit racing. Now before you buy the one for $450 does it come with fuel rails and adj fr? An don't worry about it bolting up it has holes for newer and old style heads.

Now there is something else you may want to think about this has been proven time and time again replacing stock heads with aftermarket heads will give you more of a hp gain than any other bolt on mod. You will see maybe 30 or so with the HSR, SR and MR but you'll get way more with a good set of heads.

Vortec has shown over 30+ hp gains over L98 heads
Trick Flow has shown over 50+ hp gains over L98 heads
AFR has shown 60 to 80hp gains
Dart, Brodix the list goes on an all will out perform L98s. Even ported the L98 will not produce the power across the board because of valve size and chamber design.

Now if your trying to save money and the intake is all you can afford thats cool only if your friend is doing the port job for free. If not I would buy the heads first and save up for the intake later.

 

but even with these heads the motor is being choked by the tpi. and i believe i said this already, but yes, the hsr does come with the rails and afpr for 450. heads sound great but they are so much. this is my daily driver too, and im not really looking for anything amazing. just something nice that doesnt choke my motor, gives me a little more power, and looks nice in the process.

 

That $450 does sound like a good deal and if you can get your heads ported that will only add to your hp. Also there are many 3rd gens running 12's with mildly ported stock tpi's because they do make serious torque down low and you won't have to worry about emissions. So the question is which combo will give you more hp and better performance? A intake swap with ported L98 heads or a ported Tpi with really good flowing aftermarket heads?

Hummmmmm........I don't know about this one, I think I would go with the heads first but since you are saving about $78 on the intake I guess that would be the best choice.

 

well i also found a ported tpi setup for pretty cheap. I know i can do mine myself, but this is cheap, ported, painted, edelbrock runners, 58 tb, edelbrock base...and then i can sell my stuff. might be worth it. first i need to go outside right now, i just remembered that i need to find out what size my injectors are...i was never told by the previous owner.

EDIT: I also found one of those carb manifold to efi conversions for sale from onebinky. heres what he had to say about it.

 

Don't even think about going with that junk! Just buy the HSR and get your heads ported and since you have your heads off go ahead and upgrade to a bigger cam like a hot cam. Add 1.6 rockers and upgrade the valve springs to comp cams beehive. They are about $150 for the springs they fit stock heads with no machining work. So your looking at $450 for the intake, $180 for the cam, $79 for the rockers, and $150 for the springs.

The thing about the HSR intake is that it responds really well to every mod you apply so with a cam upgrade you could be looking at 50 plus hp. Do you need a torque convertor and shift kit?

 

whoa whoa...i dont have that much money man. i barely have enough for the intake alone. plus i just figured out my tranny is not fixable so the new one will be like 200 bucks.

 

YOU HAVE TO PAY TO PLAY!

 

so you have 4 dollars and 30 cents to your name your transmission doesnt go outta first...and your worried about upgrading ur intake? You gotta slow down man take ur time do what NEEDS to be done then worry about stuff ud like to have done.

Im not understand at all why ur looking at so many performance upgrades for ur car when u have no money.

Then your worried about mpg yet ur wanting to go to carb...but i guess the other members talked u outta that...

oh and ditto on the comment before me.

 

i failed to tell you that i am getting 650 bucks next week because im selling my guitar. and also i found that tranny locally with 12k on it for 200 bucks. so ill have about 450 to tinker with, and i start my job on monday at the salvage yard. so, just planning so i know what to save up for.

 

Well just do what you originally started too do with the money.