i have a 1991 350 tpi with a p600 procharger on it. it is pushing 9-10 lbs. I replaced the spark plugs with some ngk ur6's, and now when its cold it is harder to start. it used to start the first time, now it is the 4 to 5th try. Any sugestions?????? thanks

are they the right heat range as the plugs you took out??put another set of the same plugs you took out to make sure it's the plugs first could be another problem that started at the same time

ya i found out that the new plugs i got are to cold for where i live. Thanks for the help haha

i wouldnt run a hotter plug tho, those are definitely the right plugs for the power you are making. i would check the gaps first, there isnt any different in starting power from one heat range to another, they only differ in how they dissapate heat from the combustion chamber.

What do you think a proper gap would be, i left them at what they came at out of the box, 0.38. also i havent got any hotter plugs, im leavin the UR6's in for now.

Also, i put my car on the dyno saturday, and she made 400 hp and 458 tq at the wheels. im very happy with the numbers. haha

Are they fouled or something else wrong? I run the same heat range plugs in 2 of my trans ams and never have a problem starting, even in cold weather. the only time I see a problem is when they are used for a lot of stop and go driving in traffic (the plugs are there for N2O, so in normal driving they never get pushed hard enough and tend to fowl, do a couple of burnouts up and down the street and it's OK again)

im thinking on droppin a little supercharger on my stock 350, would that turn out well or not?

DO IT!! You will love it haha.

I have a p600 procharger on mine, the only reason it was hard to start is because i am using really cold spark plugs, and i live in colorado, so winter wasnt helping.

So far i have been pushing about 8-9 lbs of boost on a stock internal 1991 350 tpi motor (400hp and 458 tq at the wheels). it has been good so far....

except for the rear end.... i broke 4 pinion teeth off the pinion gear.

O and go with a bigger procharger though.

Heh, my car doesn't like to idle sometimes, I spin the tires, it's all good for another day. I think it just likes to do a burnout a day.

haha sounds like your set and havin some fun. my 350's got a 2 barrel carb on it and no mods to any other parts, and im thinkin a 142 supercharger? whats your take on that one?
for my first car in high school, im not gonna complain with what i got haha

You'll need a bigger carb to supercharge, or you'll be horribly lean. Probably a cam too, to keep up with the increased flow.

sounds goood. im gonna have to wait on the supercharger then, cause at 15 and no job, gettin money and space for this aint easy haha

Ive been there man, i got my car with a 305 running 17.9s at slow.mph haha, in 2007, and now im a senior, i should be hitting 12s, this is up in colorado, so like 5000 feet above sea level.

I also have a 383 im working on saving up money to throw in. then hit 11s hopefully... if the trans, and rear hold

But def supercharge it, u will love it..

What fuel system are you using? are you using a speed density or a MAF setup??? I am planning on adding a blower/turbo to my stock 350 but not sure what to use for the fuel delivery maf or SD

Im using just a walbro 255lph fuel pump, procharger adjustable f.m.u., and a bbk fuel pressure regulator.. i have the fuel pressure set at about 60 psi, and it runs good. not to rich and definatly not lean.

When i do the 383 i plan on getting rid of the f.m.u. and getting bigger injectors and a tune. and run less fuel pressure.

also, i have the stock 1991 350 speed density system. no code $59 or anything. its stock.

What does it take to convert a MAF to a Speed Density????

Im to not to sure, i would just look for a speed density computer and wiring harness, and go from there. my computer has three conectors that plug into the computer, where as the maf system has just two.

Search the forums, im sure you can find where people have gone maf to speed density.

thanks for the help, i am assuming its easier to turbo a tpi with speed density rather than turbo'in a TPI with the maf setup.

Does anyone know if the MAF system can handle any psi??

Ya pry be easier with SD, but i know there are supercharger systems that will work with maf too. but im not sure about turbo/turbos and maf..

that's kind of a loaded question.... Yes, a MAF can "see" boost, they work by air passing by a heated wire cooling that wire, it figures out how much air went by, by figuring out how much power it takes to keep the wire hot. More dense air (boost) cools the wire faster, and it compensates for air temp also.

OTOH, the stock MAF setup is setup only deal with about 300hp worth, so you're not going to run much boost through it in stock form before you have to add fuel some other way (extra injectors or something, larger injectors and different tuning, larger injectors, tuning and modified maf...). In most cases it's easier to just convert to SD or an aftermarket setup that is already setup for much more airflow/fuel.