Sorry Ron I was on the fly when i posted the pic
Pls see the spex below :
3 5/16" + .030", non relieved 8BA block, short fill of Hard Block (mixed with iron shavings
Scat 4 1/8" crank
Scat 7" H Beam rods
Ross forged pistons
Custom Doug King steel caps, ARP SB MoPar mains studs
Studded heads and mains
Ported int and exhaust
1.6 Chevy valves
Custom Tatom blower cam, adjustables, Isky springs/shims, c/moly retainers
Edelbrock 1116 CNC, deep chambered heads
Hayden Mitchell blower intake
Modded pan with crank scraper and windage tray
Elec dist/MSD 6BTM/recurved Mallory dual point dist with and single point triggering the MSD box. No vaccum advance.
GMC 4-71, 2 x Stromberg WW carbs
Exhaust has been changed to Belond type headers with a mandrel bent 2" OD exhaust running through Smithy type glasspacks.
My distributor has around 16 deg of mech timing built into it - all in by 2K rpm. From the outset I had dialled in around 6 deg of initial timing and combined with the mech adv (no vac adv on this puppy) I had a total of around 22 deg of timing. Usually I like to run around 10-12 initial timing on a blown engine to keep em kool on the street and run the balance of timing via mech advance to suit the engine combo, weight of the car etc.
I have fitted an MSD 6BTM ( BTM = Boost Timing Master). As you guys know, controlling spark timing in a blown engine is of the utmost importance.This would enable me to lean on this engine while removing timing with a boost referenced setup that would (or should) protect the thing from lunching itself. From this MSD box, there runs a vac tube that connects to a bung I fitted to the intake plenum to provide a source of vacuum to allow the MSD to work correctly.
The way it works is as follows. The box has a plug in adjuster in that allows you to dial in either 1, 2 or 3 degress of timing reduction per pound of boost. So if you set it at a 1 degree reduction, then it would remove 1 degree of timing per pound of boost. Im my case at the 1 deg setting at 7 psi boost it will remove 7 deg of timing. If I set it at 2 deg, then it will remove a total of 14 deg of timing at full boost and so on.
It works brilliantly and I've yet to pop a head gasket or do any damage. This is with Premium pump gas.
The Stromberg WWs flow around 250 cfm each which is what I wanted and have a mechanical type power valves. They are set up with a direct linkage. I cant remember the actual jetting (id need to pull out my build folder) but from memory jetting was in the 50s with great EGTs and plugs look great. I've also run a boost referenced 600 Holley DP blower carb - works even better and less chance of leanouts up top, but IMO does'nt look as nice. It does fit under the hood though !
Fuel economy wise? Well, I run 3.9s gears (really would like to swap them out for 3.5s) and run a 5 speed trans with around 2400rpm @ 60 mph/100kph. She pretty good on the old benzene unless I stand on it all the time - at low rpm, there is very little boot and when coasting under no throttle vacuum reads around 18-20" Hg.
To be honest I don't really care about fuel economy as she's not a daily driver (easily could be though hehe)
Hoe this helps !
BFD