TBI camshaft, good or bad for TBI?

[1987_chevy_]

I recently had a Enginetech Camshaft (ES1095M) put in a 383 stroker that I'm building. I was told this Camshaft was too big for a TBI engine. Would it work?
I'm a young kid not knowing much about engines! But this is the camshaft the engine builder put in, knowing it was for a TBI

Specs are:

LOBE CTRS.
INT: 114
EXH: 114

VALVE LIFT
INT: .450
EXH: .460

CAM LIFF
INT: .300
EXH: .307

 

[yevgenievich]

What lsa on the cam? Need to calculate the overlap. TBI needs a cam with less overlap and generally higher seperation angle to keep good enough vacuum

 

[skysurfer]

I'll wait for the cam-knowledgeable guys to chime in but it would be helpful to know if you're sticking with the 193 swirly heads or running something else?

 

[1987_chevy_]

I am running vortec heads

 

[MikeB]

Looks like that cam has 224/224 duration @ .050" tappet lift and a 114 LSA. Sounds like a near copy of the old 350/350hp cam.

Even with the wide LSA, I'd be concerned about too much overlap (= too little vacuum for TBI) with the 224/224 duration.

Which TBI system do you want to run? And how much vacuum does it require? The aftermarket TBI systems like FiTech work well with low vacuum, but I'm not sure about a stock TBI setup. As I recall, they like 18-20".

Also, keep in mind that, even with a carb, a 224/224 cam with 114 LSA won't like compression lower than 9.5:1. And it will like lower gears.

 

[1987_chevy_]

So I'm planning on using a 454 BBC throttle body and the motor is 9.5-1 compression.

 

[1987_chevy_]

So I'm planning on using a 454 BBC throttle body and the motor is 9.5-1 compression. I was told that this cam will run about 17 psi of vacuum

 

[MikeB]

17" vacuum does sound about right for that cam, but I don't have the experience to know how it would work with TBI.

If this forum has an TBI/EFI sub-forum, I'd post your question there. Or try another forum like this one: http://www.chevytalk.org/fusionbb/showforum.php?fid/35/keyword/Fuel_Injection/

I wouldn't be surprised if you get recommendations to use a cam with 10-12 fewer degrees duration. Maybe something like 212/218 on a 112 LSA.

The 224/224 cam is gonna work better at 3500 RPM and above than it will at 3500 RPM and below. So you have to ask yourself, "At what RPM does my truck spend most of it time?" And, "Am I willing to give up a little throttle response, torque, and gas mileage for(potentially) more power at higher RPMs?"

Most engines will make good power in a band that's 3000-3500 RPM wide. So you have to choose where you want that power band. That's why you see reputable cam mfrs specify power bands at 1000-3500, 1500-4500, 2500-6000. etc. Notice that it's kind of see-saw -- when one end goes up (like more power at high rpm) then the other end must come down. Be sure to note that those specs typically assume your engine is a 350. For a 383, you can probably decrease the numbers by 300-400 RPM.

 

[1987_chevy_]

So the cam is already in the block! I would like to make it work. I posted some stuff on that forum, I'll see what they say. Thanks