Cam question.

[BEAR VALLEY]

Picked up a 1986 corvette 5.7 with port injection. I am changing the port injection to the calif smog TBI requirement for the engine my 90 Silverado blazer came with. Now what I'm asking is what cam and lifters can I add to beef the low end torque, add HP for bookin,up the highway.. Any suggestions ?

 

[1-ton]

For a TBI engine the max duration should be around 240 degrees at @ .50, with a minimum 112 degree LSA. For "booking it up the highway" I would suggest a cam that is in that range because its power will be in the higher RPM range that the engine would be working at on an Interstate. This cam would take some custom chip tuning to make all the horse power it is capable of. Single pattern cams work well with TBI engines because of less vacuum fluctuation, but those are usually only available in lower RPM range cams. The slightly higher RPM range cam I am suggesting is normally going to be a daul pattern cam, therefor requiring some custom chip tuning to make all the horse power it can.

One problem with bigger cams in a stock small block Chevy is press in rocker studs. Once you start going about .40 thousands of an inch over stock lift, this could pull the press in rocker studs out at higher RPMS. The range of camshaft I am suggesting does go over this .40" thresh hold.

 

[Bent77]

For TBI i would suggest calling Troy at Howell engineering for both the cam recommends and the tune.
Im currently running a dual profile onder my TBI at .442/.425 @212/208 @.050 lift on a 112° LSA. runs extremely well in a heavy truck

I personally havent had the stud issues at .4" lift at the valve, but I would echo the sediment that i wouldnt trust them much as the lift increases. All of my engines get screw in studs regardless of lift...

 

[1-ton]

I recently put a Comp Computer Control cam into my TBI truck engine. I went with a very conservative choice of cam. The cam I put in is PN# 12-304-4. The specs are 252/252 advertised duration, .406"/.406" lift, and 111 LSA. The reason this cam can get away with an LSA of less than 112 is because of its mild single pattern specs, which causes less vacuum fluctuation, and the 111 LSA gives it more bottom end. The stock ECM chip will be able to handle this mild cam with no problems, but I am still going to do some custom chip tuning to it, in order to get all the horse power out of it I can.

I also added a modified TBI from Vic Morse to take advantage of my cam, which increased the CFM rating from roughly 500 CFM to roughly 650 CFM. It also has an adjustable fuel pressure regulator.

 

[1-ton]

For TBI i would suggest calling Troy at Howell engineering for both the cam recommends and the tune.
Im currently running a dual profile onder my TBI at .442/.425 @212/208 on a 112° LSA. runs extremely well in a heavy truck

I personally havent had the stud issues at .4" lift at the valve, but I would echo the sediment that i wouldnt trust them much as the lift increases. All of my engines get screw in studs regardless of lift...

A stock TBI cam has roughly .385" lift. My cam increased that lift by roughly .20" over stock, and the duration was increased by roughly 30 degrees over stock. The reason I went with this cam is because I put it into a brand new GM Goodwrench crate engine, and I was not going to take it apart to install screw in rocker studs. If my engine had screw in rocker studs, I would have liked to go with a cam like yours.

 

[BEAR VALLEY]

For a TBI engine the max duration should be around 240 degrees at @ .50, with a minimum 112 degree LSA. For "booking it up the highway" I would suggest a cam that is in that range because its power will be in the higher RPM range that the engine would be working at on an Interstate. This cam would take some custom chip tuning to make all the horse power it is capable of. Single pattern cams work well with TBI engines because of less vacuum fluctuation, but those are usually only available in lower RPM range cams. The slightly higher RPM range cam I am suggesting is normally going to be a daul pattern cam, therefor requiring some custom chip tuning to make all the horse power it can.

One problem with bigger cams in a stock small block Chevy is press in rocker studs. Once you start going about .40 thousands of an inch over stock lift, this could pull the press in rocker studs out at higher RPMS. The range of camshaft I am suggesting does go over this .40" thresh hold.

Thank you much for sharing your expire nice and knowldge. I will do more homework on this. Especially the option of threading the studs. I certainly don't need them pulling out. This is no hot rod but I want a strong engine at high and low rpm. Thank you again