The cam is summit cam #1105 with 1.6's. specs are as follows:Advertised duration: 282 intake/292 exhaust Duration at .050 in. cam lift: 224 intake/234 exhaust Gross valve lift: .465 in. intake/.488 in. exhaust
Lobe separation: 114 degrees. Is this going to work? If not I will get the felpro gasket which is .051 thick. which will change the compression to 10:1. This will be a daily driver and run on premium of course. Those of you with real world experience let me know if 4 tenths will make that big of difference. Thanks

------------------

• 412ci/sb

My Homepage

 

If you use 1.6 rockers you have to make sure that your springs are tall and strong enough to handle them. Otherwise that cam should work good with a 10.4 engine.

------------------
'89 Red Formula 350- 350 .060 over forged pistons 232* @ .020 cam Performer RPM Holley 750 DP Vortec 1.94 1.50 Accel Coil and dist. Hedman shorty headers Dual Exhaust w/ cutouts 1LE WS6 suspension, wheels, and brakes, 9 Bolt 3.27 Posi Edelbrock LCA's & Track bar subframe connectors 700R4 A&A snorkel scoop Eclipse Head Unit Delco Bose Speakers 2 12" Pioneer subs w/ 400 watt/chanel amp

[This message has been edited by ATOMonkey (edited July 31, 2001).]

[This message has been edited by ATOMonkey (edited July 31, 2001).]

 

Thanks Monkey, I know the cam will work. I gave the cam specs to show if there is enough overlap.

 

It should work, but as with anything in life there are no guarantees.

Make sure there are no sharp edges in the combustion chamber before you assemble everything. That includes the tops of the pistons.

 

I wouldnt use anything more than 9.7:1 compression with iron heads.

------------------
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.23 @ 107.62 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

I'm with Kevin. 10.4 is pushing it. Depends on the engine of course..but I've seen 9.3 engines that knock if you look at them funny on 93 pump gas.

------------------
"American made baby. 100% American iron. The muscle among the masses. My hero. Yep, you can take your ergonomically designed, space age, computer controlled, 4 door, cup holding map lighted split double wishbone split fold down retractable cargo covered moon roof piece of transportation and keep it. For I have felt the thunder. And I know the difference!"
JSP Motorsports
ICON Motorsports

 

Which iron heads? Something hi-perf aftermarket or a set of Vortecs etc might take it. I wouldn't even try it then though. I'm running approx 10:1 on my Vortecs with 93 octane and no problems. but I may be off on the compression ratio... (engine rated at 8.5:1 with 76cc, switched to 64 cc. Calculator I used said 10:1, not sure if that's right or not...)

------------------
Ray87Z
-Vortec headed 350.
86 IROC w/ a cammed 305 TPI.
Formerly Ray86IROC.
www.inter-scape.com/Ray

 

It may or may not work with the cam you picked... You might need more duration to 'bleed off' excess cylinder pressure at lower RPM's to stay out of detonation. I'll give it 85% chance it will work with a fast burn chamber type. Smog heads (Straight line quence area) maybe 50% chance...

One thing I'm sure of, adding a thicker gasket isn't going to drop the compression enough to stop pinging. Actually detonation will be worse because you are opening up the quench area. Do a search on "KB Pistons" they have a pretty detailed write up on quench and compression ratio/detonation.

 

Thanks for the input guys. The heads are of the fast burn variety they are 64cc Sportsman II's. The pistons have an 18cc dish. On Dyno2000 with .036 thick gasket this yields a ratio of 10.37:1 when I change to .051 gaskets it brings it down to 10:1. I will look up that article Joel and read into it.

------------------

• 412ci/sb

My Homepage