I was piddling around with EA3.0, and was running some simulations of the 350 I have nearly finished. I had planned on putting the 76cc gm iron heads back on it and dropping it into my 3/4 ton truck. I ended up not using the isky 274 mega cam, and instead installed a comp cams 260ah-8 (260/268, 212/218@.050, .444/.444, 108 lsa, installed on a 104 ica). The compression ended up right at 8.2-1 with the 76cc heads, but the chambers on one of the heads has a wierd discoloration around the valve seats (rainbow colored :eek: ). Even though they ran just fine with no smoke on this engine before, I just don't get a warm fuzzy feeling about re-installing them. Anyway, I ran this engine thru EA3.0 with my pro-topline 200cc heads (at a whopping 8.4-1), weiand 7530 team g, 750 carb, and 1 3/4" headers. The program spit out a almost unbelievable 407hp/400#'s torque with 1.6 rockers...all on 89 octane fuel. I know its just a computer program, but I even ran this setup thru the drag analyser and with my current 10" convertor and 3.73's with slicks (spinning, BTW) it says 12.4's-12.5's in a 3600 pound car. Nahhhh....
Seriously, would a combo like this even be good for anything? Big heads, intake, headers, and convertor, with a dinky cam and compression? Would it even be driveable with the big parts on it? Have I stepped so far outside the "box" that the program doesn't know what to do with this setup? :confused:

Mot an unusual outcome at all. The cranking pressure is about 160#, and you don't really need a lot of cam to run pretty quick. To quote John Lingenfelter:
A strong cylinder head will always make more power even if poorly matched with the cam. A weak cylinder head matched with an optimized cam will never perform as well.
There are many performance motors built around a 9:1 compression limit. I assume you left all the accessories off. Motortecmag used to have a detailed article about a 404 fwhp G/S Nova that ran 11-teens at 118. He now holds the record in the high 10's.

I think the computer is going to be reasonably close in this case. However, the computer cannot simulate driveability (not that I see a prob with this combo) just that the computer calculates everything based on WOT and doesn't even start to predict throttle response, etc.

The driveability is one thing I was wondering about. I've seen some pretty impressive dyno figures on engines with stock or very mild cams and killer heads, but it just makes me wonder. What the heck, I think I'll try it...in the name of science :D

GM iron heads from early 70's on are heat treated on the valve seats. An induction heat source is used which discolors the area around the seat. That may be what you are seeing.
David

No, this was a rainbow looking discoloration only in 1 chamber. It turned out it was actually on top of the carbon :confused: I scraped it off and cleaned the chamber up...it held liquid ok overnight so I guess its ok? It ran fine before with no missing like a leaking valve, just a tad rich.

Hey Travis... did you ever build this thing? How'd it work? :confused:

Nahhh...I ended up going with one of my earlier plans and fixing the pro-toplines up and using them on the 388 in my nova. 10.3-1, 294s comp solid, etc...it runs pretty darn good but I still have this setup in the back of my mind. Unfortunately, I am over 300 miles from home so I don't get to play with my toys hardly at all anymore :(

So you are not using that 260-H8? I was kind of curious how that cam runs. smile.gif

I am using that cam in the longblock I originally posted about. 4 bolt 355, cast flat tops a whopping .053 in the hole, stock unported 76cc 882 heads, 8.2-1 compression, edelbrock performer intake and 600 cfm carb, 1 5/8" headers, dual 2 1/2" exhaust with generic turbo mufflers, and the comp 260ah-8 cam. This is all in a '86 chevy 3/4 ton truck with a built 700r4 tranny, 3.23 gears, and approx 31" tall tires. This is THE best low compression, high geared 350 truck cam I have ever run (and I have run a bunch). Very crisp, instant throttle response and a ton of power right off idle. I am very happy with it.

Where's the power drop off? Is it below 5k, or will it pull 5k-5500 no problem?

It's all done by about 5K, but then again thats about where the heads drop off too. It will rev to 5500, but up there its just making noise, not power.