69ttop502

Finally got the cam swapped and on the Dyno. Posted the old and new sheets below. Engine is an internal balance 502, 10 to 1 compression, AFR 315 heads, ported Holley Strip Dominator, ProSystems 1000 hp 4150 carb. Only thing different is cam. Old cam was a solid flat tappet. Single pattern 258 @ .050. .609 net lift on a 108 LSA.

New cam is solid roller 263 @ .050 intake, .687 net lift. 269 @ .050 exhaust .668 net lift on a 110 LSA. I am using the Morel pressure fed bushing lifter per recommendation from Chris Straub. As he said it would be, lifter sizing was perfect.

Mike Jones told me it would make 50 more horsepower at 500 more rpm. I guess these cam guys like Jones and Straub know their stuff lol. Sounded awesome on the Dyno. Both of these were done on the same Dyno, 13 years apart although the engine has only done 2500 miles in that time.

zwede

Interesting results. Any idea why your oil pressure is so much lower now?

73C34me

Very nice! I went from a solid flat tappet to a strauby roller in my 383. He promised a 50 hp gain. I didn't get to dyno it. Thnx for sharing

427Hotrod

Looks sweet! You'll definitely feel that! I like how it "hangs on" after peak.

Your original flat tappet, while only 5* smaller, it a lot different than what you installed. A while back I tested a pretty healthy solid flat tappet against a solid roller in a 555". It took a 276* flat tappet to match up to a 254* Hyd roller (both right around .700" lift) on power and overall peak RPM for HP and TQ. After that we tried a 268* SR and picked up about 25-30 HP over the flat tappet (850HP vs 820'ish). Since you were able to increase HP/TQ peaks and with the curve a roller can make...It looks really close to expectations.

I think it's very cool how close he nailed what it would do. He obviously knows his product!

JIM

69ttop502

Zwede, yes I noticed the oil pressure. Picking up the engine tomorrow and will ask the builder, but I think there is a thinner break in oil in the engine. Also could have something to do with the lifters with there pressure fed oiling to the bushing. Seems like 16 oil bleeds. The solid flat tappet lifters had the edm hole as well. Will be curious to know.

73, yes I got my lifters from Straub and I know he has a terrific reputation of picking great cams as well. They know their stuff.

Jim, yea thanks. Interesting results in your post. Can't wait to get it in the car and thrash it a little. Have a Tracdogg super 10 on the way to try to keep the rear alive.��

L88Plus

I have a set of Iskys with pressure-fed rollers that has a smaller oil passage to the rollers. It was sold as a street option to keep oil pressure from dropping so significantly at idle. Haven't used 'em yet, will post results when I do.

Les

Very impressive results! I predict a very brief and tortured existence for your rear tires. Enjoy!

roscobbc

Hi Jim, (how are you doing - haven't spoken in a while) I know most people are concerned about max HP/TQ figures - with your above comparison what was the effect at lower rpm's, like in lower speed, suburban driving - its there any 'trade-off' with the higher performing (but lower duration solid roller) ?

427Hotrod

The larger solid rollers usually drive better than the flat tappets by far. The HR would drive better than the flat tappet plus made a lot more TQ down low.

I ran an old school Crane 266/276 flat tappet with .600/.620 lift on a 110 LSA for a summer in my old 540. The regular solid roller was a 266/272 with .731" lift on a 112 LSA. The flat tappet actually performed very well at WOT...but the low speed manners of the SR was much better.

Flat tappets can run very well...but to get power anywhere close to a particular SR will take a much larger flat tappet as far as seat to seat and .050" numbers. Same with a HR.

JIM

gkull

I was just thinking with numbers like that, that your vette might take some practice to actually drive it

Like it better be going straight and moving before you go wide open in the lower two gears. Do you get tire shake?

fishslayer143

I see a differential upgrade in your very near future

69ttop502

L88, would be curious to see your results.
Les, thanks. Been wanting to do this swap for awhile. Will be a month or so before I get the car back together but should be fun!

Gkull and Fishslayer, lol yea should be fun. I do have a Tom's 1480 series 10 bolt that Tracdogg is redoing for me right now, so hopefully that will hold for awhile. Would have loved to do the 12 bolt but wanted 3.08 gears in it.

Thanks guys!

gkull

What do you use for a tranny that you would want 3.08 gearing?

7T1vette

Differential will be fine if you keep street tires on it. Stick drag slicks on it and it could throw cr@ps. Sweet numbers!

69ttop502

I am running a Richmond 5 speed.

7T1vette

Perfect all-around setup!

69ttop502

Thanks! Can't wait to be able to take it for a spin. I will eventually run the Avon tires since I am an old school 15 inch guy. Definitely won't try to make it hook on a track though I may take it down the strip a couple of times.

I figure with this cam, the 25-2600 cruise rpm of the Richmond with the 3.08 gears should be about perfect.

gkull

With your amount of TQ and 502, then the non OD tranny a 2.73 is feasible. I've used .70 and .64 OD trannys which got me into the 2.73 final ratio range and they are nice even with my higher strung small blocks.

I did get away from 15 inch because of the width and speed rating limitations. Not just that, but the traction of modern tires with the double AA and A temp rating with the ability to still run fast in pouring down rain and still be safe.

I went from 285 to 315 and then finally 335 width rears because of increasing traction problems. They have big rain grooves to channel water out.

You are going for a big TQ rear end. the next weak link might be the richmond. I hope that you have a blow proof bell housing and SFI rated fly, clutch, PP bad things can happen over 6500 rpm where you are making power.

Oh my 3/4 .134 wall roll cage made me feel so much safer............ drive line hoops.

ajrothm

Nice gain for sure!!

Also less chance of losing a lobe...maybe...

69ttop502

Yea I agree that the Richmond is probably the weak link, but I remember a Jim saying his Nash held up pretty well into the 700 hp range. I do have a Lakewood and a McLeod aluminum flywheel and am going to run the RST clutch. Ran the original street twin before.

The Avon's are a speed rated tire so should provide better traction and handling than the typical 15 inch stuff. Seems like the Cobra guys like them and use them as a rain track tire. Hopefully with the Ridetech rear, I can fit a 295 in there. I didn't know there were Vettes with 2.73 rear gears.

Thanks Alan! It is a street roller so spring pressures are almost hydraulic roller like. Hopefully with the good lifters all will be good. This thing will be driven, that's for sure! We shall see.