i got a 70s model 4 bolt main 350 that im planing on building into a 383 i plan on running the biggest cam i can without having to change stall and porting the heads im debating on keeping it tbi or goin carb what do yall think? if i stay tbi what mods will i have 2 do? also keep in mind this is a 4x4 pickup not a camaro so horse powerisnt as importnt

 

my advice would be to visit a 4x4 forum if you're not after horsepower... you're most like after torque for off-roading, right?

 

i think tbi would be better for off roading because of elevation and carburetors has floats thats hard to get it run right offroad. now a 383 tbi will require special chip tuning also. A carburetored motor would be easier to build.

 

the chip part is what scares me im thinkin it takes lot of mods to the fuel injection to run a 383 and im hear cause im a camaro boy at heart and the main reson im dumping the 305 is to go faster plus there is better info on this site than anywhere else on all my camaros i took off efi and went carb but im thinking bout keeping it for once

 

For 360-400 fwhp TBI: Carb intake with TBI adapter plate, 50mm or 54mm TB, #80 or #90 TBI injectors http://myworld.ebay.com/dctrumpet/, VRFPR, TPI or walbro 190 fuel pump and EBL flash http://dynamicefi.com/ no more chips.

Up to 350 fwhp a 46mm tb with a 46mm bored 3704 intake should be ok.

Computer cam with 114 to 112 LSA will be wery easy to tune with EBL flash.

 

You can't go into EFI "scared".

Don't go EFI because you think you "need" to.

Don't go EFI unless you are good at tuning carbs it is not "easier".
You still are tuning the same engine just with much more sophisticated tools & to a much finer degree.

If you don't relish the thought & opportunity to work hard & learn something new and exciting, then you are better off with a carb.

And

Let's get WAY over & beyond calling injectors by some kind of "flow rating" use a known part # or don't try to think that YOU are informed enough to be recommending or selecting injectors. Once YOU have studied enough & comprehend why flow ratings are so varied you WILL agree.

Just call them by their part # or don't pretend you know what you are talking about.

BTW '76, if you need a 54mm tb to make 360-400hp how is it that I'm at 480hp with just 50mm? Your advice is quite questionable in this matter.

8psi on any tbi injector is a bad idea, I guess if they are too big...
.

 

i just found a deal on a 355 it has a aftermarket cam but nothin huge and some head work its not much more than a stock motor but it runs really good and is only 300 dollars so i could easily keep tbi on it from what i read on the 305 to 350 right and should get significantly more power than my 305

 

For the 355 you described, you will need "bigger" injectors 80#/hr will probably work with the stock TBI fuel pump.

Nothing wrong with maxing out the stock TB and intake manifold, it starts being restrictive around 280hp, but for exemple, if you could make 300hp instead of 310, I would say life can be worse.

Dont be cheap on the cam, select one that matches the cylinder heads (what heads + flow numbers are must know), compression and used rpm.

With a computer cam around 112-114 LSA and EBL flash, the tuning part will be easy.

 

Almost did not notice your comment.

No problem.

I would not use the 46mm TB for 360-400 hp, 50mm and 54mm is the the next bigger size on the market, this is the main reson.

This 383 set up should work with either 50 or 54mm TB, just because a 305 can work with a 46mm or a 50mm TB, tuned.

The TB becomes restricting at point x, doesent mean hp doesn't increas after point x.

Congrats on the 480hp tbi, there is little information on high hp TBI builds.

What is bad using 80#/hr tbi injectors with 8psi at idle?

 

thomas,
Thanks for responding & giving me a chance to explain myself.
I've read your posts on this site for the past couple years & you seem like a nice guy & I was hoping that you weren't offended by my strong words.

Unfortunately I'm short on time at this moment, however I WILL use this post to get back to you on my experience & the point I'm making.

t.p.engine, under no circumstance get a larger TB or injectors, until you have proven that you have exceeded the capability of your current equipment, ie. tbi mods, higher fuel pressure, tuning ect. Your 383 will need just 550cfm @ 5000rpm. NOT the 700+cfm a modded 50mm tb can do, let alone any crazy notion of a 54mm tb.

EDIT: thomas, in an effort to save myself much typing, search member kdrolt's extensive posts on this matter of tbi flow.

Thanks,
JR

 

k thanks i think it would be worth keeping the tbi on the 355 what is this computer cam you keep refering to and i had asked in another post under engine swap about what are some other stock heads besides double humps and vortecs that can make some decent power and why no one uses lt1 heads since them motors make good power so maybe yall can answer that for me