LSA for a TBI

[Casey Price]

I'm looking at putting some 200cc intake runner heads (64cc chambers)on my stock bottom end TBI motor. I've done all the TBI mods plus a 18lb spring. Vortec fuel pump, headers and a dual plane intake.
I have a couple cams picked out but not sure whats going to work best.. Staying flat tappet.

comp CL12-268-4 XE LSA114
CL12-242-2 XE LSA110
CL12-234-4 XE LSA110

If Ya'll don't mind share what has worked for you and what all you have done..

 

[Supercharged111]

I'm pretty sure the stock LSA is close to 110, though the duration is zilch. Either way I wouldn't be scared of a 110 LSA. You are going to tune this thing, aren't you? What kind of gears, trans/stall do you have? What configuration is the truck?

 

[arrg]

Unless you plan on computer tuning, don't bother throwing that pile of parts into your truck because it won't work. If you do plan on computer tuning, you can make any of them work. CL12-234-4 isn't a Comp part number. If you meant CL12-234-2, that cam is pretty small and would have more vacuum than the others, but the fact that you want to change the heads, cam, intake, and exhaust means you will have EXTENSIVE tuning to get it to work right. It might run on the stock tune, but it won't run well.

 

[Casey Price]

I don't have a stock tune on it and can play with it some.

I'm pretty sure the stock LSA is close to 110, though the duration is zilch. Either way I wouldn't be scared of a 110 LSA. You are going to tune this thing, aren't you? What kind of gears, trans/stall do you have? What configuration is the truck?

I already have a custom chip in it and can play with the tuning. I want to say it has a 3.8something gear and no stall yet. I'm getting parts together to do the swap on a weekend.

 

[Supercharged111]

The chip that's there doesn't account for your parts list so you're definitely going to need to fiddle with the tune to make the truck happy. With that, you should have no trouble getting those cams to play ball. GM ratios are 3.42, 3.73, 3.90, 4.10, 4.56. . . At a minimum you could get a 4.3 S10 converter, that would stall 2000+ assuming you have a 4L60.

 

[PlayingWithTBI]

With those 200 cc runner heads and your cam choices you'll definitely want to tune and, get a higher stall TC since you're moving your torque curve a lot higher or it'll be a dog off the line. I went to a 2500 stall TC which helped quite a bit. Now I need a locker or LS rear end even with 275/60-15s, LOL. Depending on what you want to do, you may want to go to higher gears too. As an example when I switched from 3.42s to 4.11s I gained 3/10 sec in both 0-60 and 1/4 mile. IMO an 18LB Spring won't be enough, you'll probably run too lean at WOT and high revs.

 

[Supercharged111]

With those 200 cc runner heads and your cam choices you'll definitely want to tune and, get a higher stall TC since you're moving your torque curve a lot higher or it'll be a dog off the line. I went to a 2500 stall TC which helped quite a bit. Now I need a locker or LS rear end even with 275/60-15s, LOL. Depending on what you want to do, you may want to go to higher gears too. As an example when I switched from 3.42s to 4.11s I gained 3/10 sec in both 0-60 and 1/4 mile. IMO an 18LB Spring won't be enough, you'll probably run too lean at WOT and high revs.

And the fueling curve will be WAY off. He'll only get it right in a small RPM band. He'll likely be fat down low, good in the midrange if that's what he fudges fuel to favor, and way lean up top operating much higher than the factory intended so who knows what happens to the factory timing near 6000.

 

[Casey Price]

So what flat tappet cam would yall suggest? Something stock converter friendly until I can afford a higher stall. I have a 700r so will the 4.3 s10 converter be good?
INT--EXH
Lift 300----188--135
400----227--164
500----244--181