Don Terrill’s Speed-Talk

Looking for some opinions on the camshaft in my 355 SBC. Here are the details of the engine/car:

355 w/11.2:1 Compression (forged pistons and rods, factory crank)
Older AFR 190's Ported (280cfm@.600"), 2.02,1.60, 60cc Chamber
Ported RPM Air Gap
750 Mighty Demon
1 3/4" Headers w/3" Collectors
3600 Converter (reflashed to 4400...soon), 700R4
4.10 gears and a 26.5" Tire

All I know about the current camshaft is it is a hydraulic roller with Erson "C" lobes (whatever that means). 236/242@.050", 109LSA and .580" lift. At 3500lbs (me in it), the car has gone 11.60@117MPH (sea level) and 11.89@115 in a 3000'DA (typical conditions at Numidia Dragway). I currently shift at 6800RPM and cross the line at almost the same RPM.

I want to stay hydraulic roller. I have good lifters and push rods, a rev kit and Patriot Gold springs with Titanium dampers. I don't mind winding it a little higher. I also don't mind less vacuum at idle (currently pulls 13"). Any recommendations, or am I maxed out? I'd like to run mid 11's consistantly in the crappy central PA heat and humidity.

did ya try any spacers ?

What rocker ratio?

I have messed with a variety of spacers. The tapered 4-hole really helped the bottom end.

I have also messed with various rocker ratios. Currently, I am running 1.7's on the intake and 1.6's on the exhaust. I don't like the 1.7's (geometry is horrible), so I will probably go back to the 1.6's.

I'd recommend my part# HR74365-75365-108
288/292 @.006"
240/244 @.050"
161/165 @.200"
.365"/.365" Lobe Lift
108 LSA

Mike,

What kind of HP increase would you expect me to see and what RPM will this cam like? Oh, and thanks for taking time to look at this! Should I PM you for a price quote?

JEFF

Great recomendation Mike!

I have those same lobes in my car and they will get it done.
Will

That 4400 stall will definately come in handy with the larger cam. Its gonna spin up probably near 7K

Thanks for the comments and the PM's guys. The cam that Mike recommended is looking good to me. The cam that was in the car was custom ground and spec'd around a car that was a daily driver, fuel injected, bone stock L98 short block and 1/2 point less compression. Now, it is just a toy for my little kids and I to enjoy at the track. Pump gas...drive it to the track and race...two baby seats in the back. I don't mind the higher stall or the higher RPM's. I'd like to run 11.60's in a 2800' DA (pretty typical in the summer around here). The car hooks pretty good. I am usually around a 1.65 60' time with a little tire spin.

That old cam is a big cam for a stock shortblock lower compression L98 daily driver! What intake did you have on it? I thought the 280XFI was fairly big on my friends L98 motor with stealth ram intake/AFR 190's. It rips, but does have some lope to it. I wouldnt have gone any bigger. Your combo is doing well now tho, this new setup will definately run hard.

Jeff Pancher wrote:Mike,

What kind of HP increase would you expect me to see and what RPM will this cam like? Oh, and thanks for taking time to look at this! Should I PM you for a price quote?

JEFF

I'd say at least 30 more HP.
It's designed to make peak power at 6,600, and pull hard to 7,000.

PM me if you're interested.

Orr,

The shortblock was stock, but the heads were milled to bring the compression up to 10.5:1. With new pistons and decking, I am expecting it to be right at 11:1 (I'll measure it once it is back together). The manifold is a ported Air Gap (the old one was a miniram).

Mike,

I will send you a PM about price. Would you stick with 1.6 rockers or should I try to make the 1.7's work on the intakes? I also need to see if the timing set is for the original L98 camshaft or the more common small block patters. I also need the groove on the front for the factory thrust plate. Last question...can I get a gear that is compatible with my melonized distributor gear or will I need to go to a composite?

Jeff,

whose HR lifters are using at that RPM and what is your spring seat pressure?

mike

Jeff Pancher wrote:. Would you stick with 1.6 rockers or should I try to make the 1.7's work on the intakes? I also need to see if the timing set is for the original L98 camshaft or the more common small block patters. I also need the groove on the front for the factory thrust plate. Last question...can I get a gear that is compatible with my melonized distributor gear or will I need to go to a composite?

Since you said the geometry of the 1.7's wasn't very good, I designed that cam around the 1.6's.
We use a 3-piece billet core, so you can run your standard distributor gear with it.

Mike,

Sounds good. I will shoot you a PM.

Tokyo,

They are an old set of Comp "R-style" lifters. They sit in the dog-bone and use the factory valley spider. I set the pre-load at 1/8 turn. I also have 3/8" push rods (Trick Flow), an AFR rev kit and titanium retainers. I think all of those things help with the RPM. These are standard weight valves too...not the lighter ones that come with the newer AFR heads.

You asked about seat pressure...I think the Patriot Gold's with my installed height give 130lbs on the seat. I didn't set them up, so I am not 100% sure.