Let me DDAdv a couple of combos today inlcuding the 1103. I've used the 1102 a few times for low-end torque engines and been VERY happy - I just haven't done a lot with the 1103.

 

Thanks, I'd appreciate that. I have noticed that the Summit brand cams have the cam specs as the Crane Blue Racer line of cams. I wonder if the Summit cams are made by Crane?

 

I took a pass through this today. The caveat with DD Adv is always the quality of the data - I've created all my own flow (.flw) and cam (.cam) files and tweaked the models over time to get pretty decent results. But it's definitely a YMMV thing. I'm happy to provide the source files to any other DD owners that want to make their own runs. I *believe* the cams are Crane, although I've also heard they were Melling (?).

I'm assuming you have headers but are otherwise stock. IMHO (and just IMHO) these results make pretty good sense to me based on the specs but I welcome other thoughts/experience - all FW numbers:

Stock L-82 (baseline)................297HP@4500.... 370TQ@3500
Vortec w/L-82 (3896962) cam....340HP@5000....384TQ@4000
Summit 1103...........................314HP@500 0....407TQ@3500
CompCams 12-238-2.................336HP@5000....408TQ@25 00

 

Thanks for the info. I have noticed that the Summit 1103 and the CompCams 12-238-2 have similar characteristics of the GM24502476 cam that’s used in the 350/330HP GM crate engine. The Summit 1103 has a little more lift (.442/.465) than the GM cam but I should still be within the lift limitation correct? Also, is there any reason I can’t reuse the stock valve springs that came on the head?

On a different note, is there any magic involved in choosing the head gasket thickness? I was considering using the GM 10105117 .028 gasket. With the stock L-82 flat top pistons, I should be near 10:1 compression. Is there anything negative about running 10:1 on a street car with my setup?

 

Not sure what you're asking specifically regarding the cams - are you looking for a cam that produces more torque than HP and at a lower RPM? The specs don't tell the whole story...part of it is the lobe profile.

The springs can be reused with all of these cams except the 12-238-2, which given it's profile is going to need more seat pressure. I don't have my references here, but the CompCams catalogs are online including recommended springs. At these power levels, the biggest concerns are a) coil bind and b) float.

The "magic" in the head gasket thickness is determining quench - the distance between the head of the piston and the surface of the head. Ideal quench is around .040 for an SBC - there are a couple of ways to get there If the deck height is at a stock .025, then an .028 gasket gives .053...which is a bit high but way better than .066 you'd get with an .041 gasket. On a new build, a smooth deck and head surface allows running an .015 metal shim gasket for .040 quench, or you can cut the deck to allow for around .040 with an .028 gasket.

I didn't "do the math" on the CR, but after about 9.4 or so premium gas is required for full ignition advance. There are a TON of variables here - dynamic compression ratio, etc. but I would say with some confidence that 10:1 CR is going to require premium gas.

All IMHO, of course

 

I know, thats what I have been wrestling with. The L-82 cam is a good cam. What do the torque numbers look like between 1500 and 4000 RPM.

 

I can re-run these tonight (I didn't save 'em) and post the charts - but in general my suggestion would be to decide where in the RPM range you want the power...and pick a cam to match. That's kinda the point of this exercise - to get what you want

There are a couple of GM cams that have really stood the test of time and this is one of them...if you have the gears.

 

I supplied Lunati, Crane and Comp my setup info, below is what they recommended.

Lunati Bracket Master
part# 00017
224/224
LSA 112
Lift 0.460/0.460

Crane Z-Cam
part# 113512
212/218
LSA 114
Lift 0.446/0.459

Comp XE262H
part# 12-238-2
218/224
LSA 110
Lift 0.462/0.469

I'm leaning toward the Lunati Bracket Master II Cam. It's got good lift and LSA numbers. Billla, can you run a DD Adv for me with the Lunati 00017?

Using the formula here http://www.carcraft.com/techarticles...tio/index.html
I calculated my estimated compression ratio to be near 10.1:1

 

This post has got me thinking about a cam swap.

I have a 76 L-82 w-4spd. I've had the car for a few months and it runs well. It is totally stock besides Comp Mangnum Rockers, and pioneer 943-4 springs. The engine and heads were rebuilt 8 yrs ago and has 12k on it. It was rebuilt professionally by Tucker's GM Performance in Las Vegas.

I'd like to make some more power, but don't want to break the bank while I'm fixing up other items on the car.

I'm thinking true dual exhaust and a comp xe262h cam and lifters and I'll be seeing some good gains on the cheap, and potentially more if I swap heads and intake later.

Any thoughts on this strategy? Will I need to run the comp springs too?

 

When I rebuilt the top end of my 79, L-82 I wound up spending approzimately $550 for new guides, springs, machine work, screw in studs, etc. I would have been money ahead to have purchased a set of modified fastburn vortec heads for just a little more money.

 

The 12-238-2 was my recommendation - and I'd stand by it - but here we go for the Lunati:

Here's the cam card:
http://www.lunaticams.com/Product.aspx?id=1784&gid=245

And the data I got from DD Adv:

345HP@5000RPM, 422TQ@3500

Compare to 336HP@5000, 408TQ@3500 for the 12-238-2 and there's a definite improvement, and it's also better than the stock L-82 cam 340HP@5000, 384TQ@4000 - looks like a winner pick to me

Need to note that these are all within a couple of percentage points, which is the margin of error. YMMV

 

Thanks for the feedback, cam decision done. Could you post or PM me the DD Adv. HP/TQ graph for the Lunati?

 

I am running that cam with a set of ZZ4 heads getting about 9.5/1 comp, nice torqy eng for street use, good pull from 2000-5000 rpm's. Def not a race set up but works well for 'spirited' back roads driving

 

Well, I talked to the folks at Lunati today and they said the 301A8LUN would also be a good fit for my setup. Great, another choice
http://static.summitracing.com/globa...n-301a8lun.pdf

Seems large exhaust duration wise but has safe lift number for the Vortec's. It's supposedly a relatively new grind designed by the same guy that did the Voodoo line. Billla, It would be interesting to see the DD on this one.

 

compare to 301A8LUN

p/n CS1062R hyd flat tappet 220*/231* .465"/.480"
This one's been in Sealed Power cat for awhile ... Ralph's had it in an alum head 10:1 scr 355" C3 for at least 2-3 years ... he's very pleased. And 1/2 lunati $ too.

FYI ... sealed power aka speed pro aka federal mogul FKA TRW ... most OE vortecs will handle .480"

see posts 3 & 6
http://www.corvetteactioncenter.com/...d.php?t=100700

cam only $83
http://www.northernautoparts.com/Pro...ctModelId=4239

16 lifters $30
http://www.northernautoparts.com/Pro...ctModelId=9029

cam & lifters $163
http://sealedpower.carshopinc.com/pr.../48850/KC1062R

 

I'll run the DD tonight; busy time of the year for me (end of FY)

I've had a couple of sets where even .475 was on the tight side a bit - but the key message is check your clearances