383 - 496" stroker cam question?

Looking for camshaft suggestions for a 383 496" stroker.
This combination is way different with the short 1.538:1 rod ratio.
This is the flat top, 4cc valve relief, 84 cc head (RPM), so at 0.060" over I am coming up with 11.37:1 compression.
Want to run pump gas, and this is a street car, not a racer so looking at street friendly lobe profiles.

With the lower rod ratio, will it want a cam with the wider LSA?

I am thinking a cam like the Comp XR292R but with 112 LSA and installed around 108 to 110 centerline?

The specs would be something like Advertised 292/297, 0.050" duration, 254/260, 112 LSA, 110 CL

In theory that calculates to 7.82:1 DCR compression and 159 cranking pressure?

Anyone build one of these

Did you read this article: http://www.hotrod.com/articles/dyno-tested-make-700-hp-trick-flows-new-fe-heads/

We used a XR292R-10 street roller in it. It is roughly the same size of engine that you are talking about (482 vs. 496) and similar compression ratio (11.37 vs. 11)

The XR292 works great in an engine this size. It is big enough to make plenty of power but small enough that the idle should be half way decent. It won't idle like a Caddy, but it should have decent vacuum and be driveable if you have 3.23 or 3.54 gears.

Here is another article I did but this one is a 505 Mopar with Edelbrock heads and a HR 292R cam: http://www.hotrod.com/articles/1007phr-big-block-mopar-engines/

Thank Andy. The parts I am looking at are the low rod ratio and if the cam should have a wider LSA because of it? The GM stroker guys with rod ratios like this seem to like cams with 114 LSA?

Also, I think it might make the cam more street and octane friendly?

When I plugged the specs into the Dynomation 6 simulator, it seems to like the wider LSA too.

I guess the question is if it is worth messing with the cams LSA compared to the off the shelf cam designed for a longer rod ratio engine?

You aren't going to find anyone who knows the answer to that question for your engine since it depends on the interaction between a bunch of parts. And I'll bet that it doesn't matter at all in a pump gas street engine. But if you want to put it on 112 rather than 110 I doubt it will hurt anything.

will it want a cam with the wider LSA

Narrower: short rod makes piston motion faster around TDC.

LSA is just a number, it's derived from your cam choice - it doesn't determine your cam choice.
You will see references to a big LSA, but it' not relevant - that's a cam with so much duration (280° @ .050") that opening it up makes the actual OL window closer to what you'd expect.

Vizard's guess as estimating the actual area when both valves are open: proportionate to the OL in nominal (not .050") degrees, squared, × .01.
E.g., IO 40° BTDC + XC 50° ATDC = OL 90°: OL area = 81 "units". Small changes are important, going from that to
IO 50° BTDC + XC 60° ATDC = OL 110°. Looks like +22% (110 ÷ 90)?, but the OL area = 121 "units", 49% larger.

My 518 C.I. 400 block pump gas stroker motor had 6.800 long rods with the 4.300 stroke crank shaft so it had a 1.58 rod ratio, the cam I used and liked a lot was a Comp Cams custom ground solid roller that had 260@.050 with .420 lobe lift on the intakes and 266 @.050 on the exhaust lobes with .409 lobe lift. It was ground on a 108 LSA and I installed it and tested it from 105 to 107, I also used a set of Haralnd Sharp 1.65 ratio rockers That motor with a set of CNC MCH ported RPM heads with a low deck six pack and 440 carbs. ran super well
That motor had 10.29 to 1 compression ratio with that set up, no quench at all
It liked to be shifted at the track at or above 7000 RPM to go as fast as the car would go, shifting it any lower would slow that rascal down

The off the shelf, 110 LSA cam looks OK to me?, but was curious about the wider LSA for a few reasons.

Just some ideas I'm throwing around:
The engine has what looks like a good amount of compression at 11.37:1, but want to run it with EFI on pump gas.
I think the lower rod ratio will help with the pump gas part because the piston is not going to be near TDC for very long?
Backing off the installed intake centerline should also close the intake valve a bit later lowering the DCR?

I will get the suggestions from some cam grinders too. Just checking if I am way off base as this combination is a bit different than what I have done before.

Jim,

Are you correcting your numbers for your altitude?

I've noticed your past builds were sea level type combos and always wondered why you didn't add at least 20% more mechanical compression. Your 11.3 theoretical is closer to 9.0:1 @ 5,000 D/A.

A wider LSA can also have more detonation in the part throttle low to mid rpm, because it has less EGR affect of the overlap.

Lots of street combos actually like wider LSA's and the wider units can surprise you on the dyno--most folks have always went with the old 108 stuff so it has that sound they all crave ( that being in a 440) in the bigger CI Mopars they soak up cam size pretty fast
The older I get and with the way I drive now the wider I like them for great overall performance but for customers sake and getting that coveted "sound" on the bigger CI I usually end up with 110 and never go past 112 Your cam choice looks fine to me for a hot stroker I would not think about it more than three seconds based on rod length--the way I see it you will have less piston noise and that will be a plus you did not bank on compared to say a 7.100 rod hockey puck piston

Opinions are like... oh never mind.

I think that cam profile is very reasonable. I also think you are pushing compression for a pump gas street engine. By at least 1 full point. Hard to compensate with the cam. I hope I am wrong and please post how it turns out.

It's not my engine. My friend already has the heads and stroker kit, and wants to drive here and at sea-level on pump gas.
Really, for the application, I would have gone with the 20cc dish pistons, about 10:1 compression and use a smaller cam.

The old 451 engine was a 11:1 engine with less quench, and a tad less cam (251 @ 0.050") than this one.
It should make for a really strong engine, but the pump gas part is the question?