Camshaft with EFI?

[jdogdude78]

I am putting a Lunati Comp cams Xtreme energy retrofit camshaft in my 347 dart engine.
I have seen this cam put in the almost exact engine set up before, but only difference is they had a carb and I will have a Holley sniper EFI.
Is there any reason to believe this would be an issue with my engine?

Justin

[GoDadGo]

I am putting a Lunati Comp cams Xtreme energy retrofit camshaft in my 347 dart engine.
I have seen this cam put in the almost exact engine set up before, but only difference is they had a carb and I will have a Holley sniper EFI.
Is there any reason to believe this would be an issue with my engine?

Justin

Justin,

Most EFI-style camshafts have a lobe separation angle of 112-114 degrees.
Many performance Carb-style camshafts have tighter separation angles of 108-110.
What's the camshaft part number and specification because your delivery styles do make a difference?

Steve

[jdogdude78]

Thank so much for the reply.

This is the part from Summit Racing

Cam and Lifters, Hydraulic Roller Tappet, Advertised Duration 294/300, Lift .576/.600, Ford, 351W, Kit

CCA-CL35-427-8

I believe it only has 110 degrees lobe separation

I am assuming in needs to be greater so the intake and exhaust phases don't overlap?

[Mike N]

The 110 LSA will produce a lower idle vacuum. Not sure if, or how the Sniper will react to that.

[GoDadGo]

That cam may be a bit problematic in the low-end torque department depending on your gears and your combination.
I'd check with Holley's Tech Area & Comp Cams too if you haven't purchased either component.
Also, that 110 Separation Angle may not play well with the Holley Sniper E.F.I.
I was running a similar grind pattern before changing my block.
I dropped down to a smaller bump-stick and am glad I did.
Please know my car is Carburated and runs fine.

My Specs Are Shown Below:
https://www.factoryfive.com/whats-new/customer-steve-l-graduates-his-mk4-roadster/

[FF33rod]

Here is the comp cams description

Xtreme Energy™ 242/248 Hydraulic Roller Cam and Lifter Kit for Ford 351W (Not for EFI) street/strip applications. 9.5:1 Compression, intake, headers, 3000+ stall and 4.10+ gears. Rough idle. (Note: For Engines That DID NOT Come From The Factory With Hydraulic Roller Cams

Red flags: not for efi, 4.10 gears, huge lift

I doubt this cam is a good idea. Call comp cams and tell the your specs so they can make a recommendation. You will need to know rear end gear ratio, piston valve clearance, compression ratio, transmission...

Steve

[jdogdude78]

Thank you very much guys.
Appreciate the help

[Papa]

The Sniper wants to idle at around 800 rpm or more, so if you want the lumpy cam idle, go with a carb.

[jdogdude78]

Guys,

Thanks so much for the responses.
All had great learning points.

I went on the comp cam site and gave a tech all the specs of my set up and they recommended a camshaft.

[Geoff H]

Just curious, what did they recommend?

[jdogdude78]

XFI Computer Controlled 236/248 Hydraulic Roller Cam for Ford 351W
XFI™ Computer Controlled 236/248 Hydraulic Roller Cam for Ford 351W. 347” Or larger. Super strong mid-range. Best w/ 9.5 to 1+ compression aftermarket heads, intake, T-body & injectors. 3000+ stall or 5-speed. Computer mods required.

lobe separation 114

Intake at 0.05 inch lift 236/248


This discussion prompted me to really try to get a basic fundamental understanding of a camshaft and how it works.

[Mike N]

That's still a big cam for a street engine. Depending on what you expect from the car you may love it or hate it. In a 347 expect peak power at or above 6500 rpm and not much below 2000 rpm. IMHO something with about 10 degrees less duration on both the intake and exhaust would give you a very strong yet drive-able street engine.
https://www.youtube.com/watch?v=vuC5fwP1s7w

[Sdonnel]

While not the Holley system, I'm running an Isky cam with my Fitech. Has the specs listed below. While I don't plan to spin my motor past the 6,500 peak on the cam, the lope sounds great at 875 RPM. Pulls like a freight train and does not lug at all in any gear. Tried to add a video clip of my idle with no luck. PM me with an email address and I will send it to whoever wants it.

Valve Lift Int/Ext. 0.520/0.544
Valve Lash Hot Int/Ext. 0.000/0.000
ADV Duration Int/Ext. 275/284
0.050 Duration Int/Ext. 228/238
Lobe Center 112