hi i just baught a 87 iroc z28...finally a car that runs i had a 78 camaro that i had to pull the engine so i making a 383 with that engine (68 327 from impala) but any ways ive been readin up alot about the carb swap but i cant seem to find and info on the hp rating...i would jsut like to no how much of an increase i would b getting...i plan on putting a weiand intake and holly 750 vaccum secondary and an accel disbributor cap with coil...and i wanna put headers on it as well. plus i wanna do a few of those little mods, i would like to no the 1/4 mile times as well if that is possible.
thanx, Trevor

 

Welcome Aboard!

There are a lot of variables there, and you haven't even listed them all. Much of what you'll get will depend upon the heads, cam, how the carb is set up, axle ratio, transmission, etcetera.

The '68 327 heads are not going to feed a 383 well.

Further, since the L98 cars were equipped with an automatic transmission, what are you planning to use in place of that? The original trans in stock form is not going to work with a Holley 750, guaranteed - You'll have no TCC lockup.

As long as you're getting an Accel distributor cap, you might as well get the whole new distributor, since the stock distributor will be all but useless with the Holley. There will be no timing advance, and you might be lucky to make 200 HP with your fresh 383. That's quite a change, since the original L98 was already making around 230. Expect about 16-second times, or right about on par with a Honda Civic.

 

hmm i should have given more info , my heads have been ported and polished and have 2.02/1.60 valves, i am gettin a full msd kit for this. I no my heads are not gonna flow like the best but they should do pretty good for now until i can afford sum AFRs. and the 383 wont b done till next summer, im goin all forged, big cam, victor jr intake, etc.

but as for the carb swap on the tpi ,for the tcc isnt there a switch u can wirre up to it? also along with the tranny im getting the manual valve body and shift kit for this summer and rebuilding everything over the winter.

and i jsut wanna get rid of the tpi stuff on the 350 and make it carb, but while im at it i gonna get a new cam and valve springs (possibly lt4 hot cam) , ditch the smog and ac stuff and put a set of headers on. but i have the accel cap and coil on a vacum advance distributor so i can use it with the carb. also i gettin a fuel regulator but i am wondering abotu the stock fuel pump? could it work or should i get a new one?
as for gears in this they are goin to be stock this year (3.23?) but im planning on getting a set of 3.73 in the future.

 

Wanna send me your factory distributor out of the car?

 

You can test the fuel pump fairly easily with the engine in or out of the car. As long as it will deliver a half-gallon/minute, it should be good.

You can use the TPI in-tank pump so long as you install an external 3-line regulator to reduce to 3-5 PSI, and use the original return line to the tank.

As long as you're going with a different distributor, the carb won't matter - Use whatever type you want.

You can remove the ECM completely and install a control for the TCC lockup on the trans. I believe Transgo or TCI makes a kit, and it is more than just a switch, since it uses the 4th gear switch in the trans with a relay and some other logic (brake pedal switch, etc.). But it can be done with a little work.

 

thanks alot for the info vador ill keep updates on everyhting and post sum pics of the car when i get them

 

Be sure to keep your oil pressure saftey switch for the fuel pump connected. You might rewire the switch to isolate it from the ecm but you need to run a saftey cutoff switch.
A classic formula for determining the cfm neccesary of a carb requires only the engine displacement and peak power rpm of the motor . For your 383 you will prolly find that @ 6500 rpm 675 cfm is about all you want. Over carbing will just make it difficult to tune.
Big cams dont do anything without big heads. If you plan on switching to AFRS make sure your parts are adaptable or else youll end up rebuying a lot of parts.
A camaro with a well built carb'd 383 with afr heads shold be able to run 10's with sub frame work and suspension tuning and some 10 inch slicks, and whole lots of other stuff.
There's no problem with playing around with a setup and mixing up parts, but keep in mind its not likely gonna work any part to its highest potential and its gonna cost extra money in the long run.
My Op: drop a well built 383 with AFR heads right from the beggining(even if delayed). Take time to get just the right cam for your head flow values, exhaust setup, trans, street/strip, etc. AFR, or the group who did your heads would be happy to help you pick the right cam, exhaust etc. If you want to make LOTS of power, theres no question, the afr heads(aftermarket alum in general) are the trick. Theres no Replacement for Displacement, either.

 

If you replace all the necessary parts to change it from a STOCK tpi 350ci to a carb, I have read that you will actually make more hp with a 750 and a decent manifold by about 40 hp with headers. You will lose torque by about 50 lbs-ft though.This info is coming directly from TPIS and not my a$$.

 

You could a 750 without a doubt , but will be pretty tough to tune, youll probably be dumping more fuel than you really need aswell.....I think.

 

a 750 cfm is great for a 350 especially if it has a cam. In summary you need a vaccum advanced dizzy, carb.,tcc lock up stwitch, and fuel pressure regulator and you should be good to go. But if i was you i would just run the tpi until you have the 383 built but thats just me. good luck.

 

im in the process of building a 383 myself, and i am throwin a carb setup on the stock 350 now, mostly because im redoing all of the electric in the car now and just figured that it would save myself some time to wire it now, and build it up later

 

i have an 87 iroc, im looking for the the rubber hose feedline it has a 3/8 hose , it will have 2 female fittings on it that attach to the steel fuel lines
thanks
devinea@shaw.ca any help would be appreciated