I read a great deal here but post very little and thanks to you all for all of the wisdom I have gained from this site! I started a project and now I am deep enough that I get a different opinion every where I turn and I could use some help.

I got a 5.7 long block cheap...free...from my old man. He started the build a long time ago and lost interest so I swapped him some parts for it. It is a 2 bold main 40 over with a Holley system max upgrade which includes the following:

Vital Statistics

Engine production years: 1968-86
Horsepower: 425HP @ 6150 RPM
Torque: 425 lbs./ft. @ 4250 RPM

Kit Contents

Lunati hydraulic camshaft and lifters,

Holley dual plane aluminum intake manifold,

Double roller timing chain and gears
Fully assembled Holley aluminum cylinder heads,

P/N 300-552-1

Hardened push rods,

ARP

Assembly lube

Camshaft Specifications

Intake valve gross lift: .488”
Exhaust valve gross lift: .510”
Intake valve duration @ .050”: 234

Exhaust valve duration @ .050”: 244

Rocker arm ratio: 1.5
Intake valve lobe centerline: 107

Lobe separation: 112º

I live in CO and this motor will see some huge variation in altitude so the Holley 750 was to be replaced with a EFI of some sort. I decided that TPI was the way to go thanks to the low end torque it provides. I have been told that this cam is to wild for a stock TPI unit and that a RAMJET is the way to go. I am at the point now where ignorance can cost me a great deal so I was hoping you all would help get me back on track.

Shoule I replace the cam?
Should I resell the TPI and go with a RAMJET intake?
Should I .......

Thanks in advance for the feedback!

 

What car is this long block going into? Where did your TPI come from?

About everybody who has a 350, thinks that the factory TPI stuff limits the output of the engine. I would recommend the Holley Stealth Ram.

Also, that cam is fairly big for a 350 and may be alittle computer unfriendly with the high duration coupled with the 112* LSA.

Couple other things to look into:
1) the EFI ECM needs an electronic distributor.
2) is the block drilled and tapped for the various EFI sensors?
3) being located in Colorado, I would run a MAF ECM.

 

That cam has too much duration for its low lift. Get rid of it. It will be a tuning nightmare, and it won't make the HP for it to be worth how dirty that thing is going to run at lower speeds. You want more lift and less duration. I have the marine version of the Comp 280HR cam. It is the same as the car version but it has a 112 LSA instead of 110. 0.502/0.510", 224/230 duration @0.05. It still has an agressive idle. I just read an engine build wher this exact cam was used in a 383 build and they made 510 hp with it on the dyno and more than that in torque.

EDIT: I just realized you have a flat tappet block. THat is going to limit you. I would run the Comp 275 DEH cam (0.462"/0.482", 219/229@0.05. I have run this cam with TPI based EFI w/ a holley stealth ram, and it made great power up over 6k in a 327.

You have to burn chips though. None of these cams will be even remotely okay without tuning.

 

Thank you for the feedback!!!!

I was actually looking at a marine cam already now that I have been digging deeper. How does this one look?

CamshaftsPart Number:CCA-12-232-3
Cam Style:Hydraulic flat tappet
Basic Operating RPM Range:1,000-5,000
Intake Duration at 050 inch Lift:212
Exhaust Duration at 050 inch Lift:218
Duration at 050 inch Lift:212 int./218 exh.
Advertised Intake Duration:256
Advertised Exhaust Duration:262
Advertised Duration:256 int./262 exh.
Intake Valve Lift with Factory Rocker Arm Ratio:0.447 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio:0.462 in.
Valve Lift with Factory Rocker Arm Ratio:0.447 int./0.462 exh. lift
Lobe Separation (degrees):112
Intake Valve Lash:0.000 in.
Exhaust Valve Lash:0.000 in.

Knowing what I know now I like the looks of the cam you suggested and since this one is a bit milder I will runn less chance of clerance issues with the piston I suppose...

I was going to build a harness and use a MegaSquirtII for control so I will have endless tuning options.

With one of the above cams would I be able to stick with the stock TPI or will I still be starving the motor of air?

 

Here is another one I am looking at:

Basic Operating RPM Range:600-4,600
Intake Duration at 050 inch Lift:206
Exhaust Duration at 050 inch Lift:214
Duration at 050 inch Lift:206 int./214 exh.
Advertised Intake Duration:250
Advertised Exhaust Duration:258
Advertised Duration:250 int./258 exh.
Intake Valve Lift with Factory Rocker Arm Ratio:0.432 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio:0.453 in.
Valve Lift with Factory Rocker Arm Ratio:0.432 int./0.453 exh. lift
Lobe Separation (degrees):111
Intake Valve Lash:0.000 in.
Exhaust Valve Lash:0.000 in.

Looks like that one may be mild enough for a stock TPI intake and produce some low RPM torque at the same time...

 

Go with a retro-fit hydraulic roller Comp Cam 280HR with a 112LSA