Best/Worst decision when ordering SPF MKIII

[greg schroeder]

Originally Posted by jmorganw

Greg,

Thanks for the info. Looks like you get close to 50 in first which is about where I feel I want to be. I am a little surprised you rev to 6500. The Rousch site states Max RPM 6250. I am planning to have a rev limiting ignition and thought I might limit to 6000.

What sort of rpm do you have in top gear at, say 70 mph?

Can you tell me something about the headers? I seem to understand that the standard ones don't quite match up with the engine. Don't know what the diameter of the standard headers is.

I use a 6800 rpm rev limit. It over revs now and again to around 7000 as I'm all fired up going through the gears. From what I understand not all cam specs are the same in each 427R. Roush has declined to give me my cam specs. I have 427R-095 which seems to pull great up to 7000 rpm with the Pro-Systems 1000ish cfm carb.

Here's the RPM page from the above run. There was some wheel spin at start so that's why it looks choppy in the beginning. The tires on rear are Mickey Thompson ET Street drag radials, 325/50 15. They're not actually 28 inches tall as their site says, but rather about 27 inches.


My Superformance small block headers covered .3 inches of width on each exhaust port for the heads on my Roush 427R-095. The height of the Superformance header opening is too tall. The heads are AFR 205s built for Roush. The headers I got from the Olthoffs were 900 dollars and have a slightly larger diameter than the AFR 205 exhaust port. They look just like the Superformance headers, but are 2 inch primary instead of 1 7/8 and have a new flange welded on then re-jet coated. I aligned the pipes to heads even on the bottom with the over size at top to more center the highest exhaust volume location within the exhaust port below the bend in the pipe at top.

I don't recall my RPM in 5th gear at 70, but it's quite comfortable with the .64. The 4th gear is a 1.0.

My side pipes are on order from Buckshot Racefab.
http://buckshotracefab.com/

My new half shafts are coming from the Drive Shaft Shop in a few days as I shattered the splines on one in the left side in the differential.
http://www.driveshaftshop.com/

I'm putting on a larger size fuel line for the mechanical fuel pump that came on the Roush 427R-095. I may buy a 130 gph pump with regulator next if I do a 50 HP wet shot Nitrous oxide system.

[jmorganw]

Thanks again Greg,

I am not a mechanic so some of these things are outside my ability, but the headers are not, and while I want to have "bragging rights", I may never fully utilize the power.

I looked up the carb company, Pro Systems and will investigate that too. I do want power, but since I will not be going for the max I am really interested in drivability first and power second.

[Bill Wells]

jmorganw :

the Pro Systems custom carb gives you BOTH driveability and power. i recommend them for street cars never expecting to see the strip or track , as well as the racer folks. their carbs are superb outta the box :

see ; http://www.pro-system.com/

they have built two carbs for me for 2 different applications....excellent all around performance, and mine are without chokes yet start right up -even after storage. bill