roller cam and lifters

[allweld488]

I have a 87 with a 92 engine 5.7 tbi, now I want to retain the tbi but would like to put in a roller cam and roller lifters, I would like to put the largest one I can without computer mods, whats your thoughts. by the way this is bored .040 over with flat top pistons and decked to .015 with the valves opened up to 2.02, not sure if any of that matters in roller cam selection on a tbi engine.

 

[Driver4r]

I have a 87 with a 92 engine 5.7 tbi, now I want to retain the tbi but would like to put in a roller cam and roller lifters, I would like to put the largest one I can without computer mods, whats your thoughts. by the way this is bored .040 over with flat top pistons and decked to .015 with the valves opened up to 2.02, not sure if any of that matters in roller cam selection on a tbi engine.

If these are still the 193's. Why did you put that time into swirl ports? Jw.
And is the block tapped for a roller cam?

 

[allweld488]

Yes the block is tapped and ready for roller cam, The heads where done by previous owner just before i bought the truck.he had someone build this motor for him to the tune of 4k, (he gave me the reciept), and got ripped off bad, the motor only lasted about 10k miles and was suppost to have a roller cam and lifters in it. when i took it apart it did not, it was also suppost to have flat tops in it, it did not.the only thing on this reciept that i can tell he did was cut the heads out to 2.02, this block is cuerrently out to machining now and i will be building it hopfully in the next few weeks, this is why i am looking to decide on a cam. i am not looking for crazy horse power just trying to pep it up alittle.

 

[bucket]

TBI is the limiting factor, it won't be happy with much more than a mild cam.

 

[MadOgre]

I would use a FAST MPFI if you want to retain fuel injection and get the cam of your choice or throw on a Carb for now if $ are hard to come by

 

[Joe383]

I would look at a used LT1 cam on ebay.

 

[MikeB]

The GMPP fuel injected RamJet 350 uses a roller cam, but I don't know if it would work with stock EFI. The price is certainly right and it's got more lift and duration than a stock cam, but still places an emphasis on torque. http://paceperformance.com/i-6255412-14097395-hydraulic-roller-camshaft-ht383-crate-ramjet-350.html

And the kit below has lifters and everything else you'll need, except for cam retainer plate. And you will need shorter pushrods, but I wouldn't order them until the heads are installed and you can measure for proper length.

http://paceperformance.com/i-625512...ie-bars-ties-bar-holdown-spring-hardware.html

Here's a RamJet 350 HP/TQ chart. Of course, the engine also uses Vortec heads which are good for more TQ and HP than 1980s & early 1990s heads. Gotta love the flat TQ curve -- perfect for trucks. Actually it's perfect for most street vehicles, but lots of guys will say the cam is too small because HP peaks at "only" 5100 RPM.

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I'd also suggest you call a couple of cam companies to see what they recommend. They'll ask you about your goals for the engine, transmission type, and rear axle ratio.

 

[Joe383]

If you use a factory GM roller cam you have to replace the cam gear with one that's melonized or you will eat the teeth off of the gear. There about $50 new. Most aftermarket cams don't need them. The factory vortec cam is about as large as I would expect you to be able to go with out tuning. Even the LT1 cam I think you might need to tune with. You might get away with just upping fuel pressure a little with an adjustable fuel pressure regulator with the LT1 cam.

 

[MikeB]

Yep, you will need a GM melonized distributor gear. I'm gonna use a real GMPP HEI or maybe a Proform, both of which come with that gear.