I am looking to convert my gas Blown BBC to alky, After reading a lot of the topics that I find on this website. I am being to think that along with all the other stuff I am getting ready to do that it might be a good idea to replace my pistons as well.
Current engine set up:
BLOCK - 4-bolt main 427 seasoned block bored .030 oversize. Block is hot tanked, custom honed, dry decked, line honed, new cam bearings installed. Brass freeze plugs installed. The Outside of the block is painted with your choice of factory colors.
CYLINDER HEADS - New RHS™ Pro Action cast iron rectangular port cylinder heads castings feature 320cc intake runners. Stainless 2.250 & 1.88 valves. New perf valve springs which will handle up to a .600 lift cam. (Larger cams or solid lifter cams will require optional valve springs at extra cost.) Stud girdles installed.
PISTONS - Forged supercharger pistons. 7.3 to 1 static
RINGS - Premium Speed-Pro moly rings.
RODS - P.A.W. 6.135" high performance connecting rods which have been shop-peened, checked for straightness. Resized on the big end and fitted with high performance 3/8" chrome moly rod bolts for maximum strength and performance.
CAMSHAFT - Your choice of a new P.A.W. / SSI hydraulic cam to match application.
LIFTERS - New P.A.W. hydraulic flat tappet to match your cam.
CRANKSHAFT - Factory steel crankshaft precision finished at .010 under on both mains & rods journals and machined for dual keyways!
BEARINGS - New Clevite M77 - Top quality rods and mains bearings.
TIMING CHAIN SET - New P.A.W. double roller timing chain set.
GASKETS - Fel-Pro engine gaskets set along with a pair of SCE ICS Titan copper head gaskets with stainless O-ring wire.
OIL PUMP - New P.A.W. high-volume oil pump to provide maximum protection.
PUSHRODS - New P.A.W. 3/8" chrome moly high performance pushrods.
BALANCED - Electronically balanced rotating assembly, pistons pressed on to rods. Advise salesman if using flex plate or flywheel.
DAMPER - Special damper for use on supercharged engines with dual keyway.
ROCKER ARMS - New P.A.W./SSI long slot rocker arms.
SUPERCHARGER - Complete 6-71 supercharger 8% over driven
HEADERS - 1 7/8 primaries to 2 1/4 colletor. 2 1/4 out the back through Supper 44 Off Road Mufflers
CARBS - 2 Demon 650 Blower Carbs
TRANS - Built 700R4
TRANSFER - NP 241
REAREND - Currie 9"+ 35 spline Axles Detroit locker 5.13 Gears
IGNITION - MSD 6AL Box, MSD Distributor, and Mallory Coil
While tuning on a chassis dyno in a 6000 lb truck, @ 5000 rpm 3rd gear it made 344 hp and 378 lbs torque. The guage was showing 10 lbs of Boost. This is turning 39.5 x 18 Super Swamper Boggers. We were not going of all out HP. I just wanted to make A/F ratio was safe. I am sure to a lot of you I am not making crap for HP and Torque, but this is my first experience with Blower engines and bought the engine preassembled. Trying to make it better as I go.
Now to the mods in the near future.
Hilborn EFI with FAST XFI system
ALCOHOL for fuel
ARP Head studs.
Now my question, with the information that I have posted above I am looking for input on 3 subjects,
1 How much Horse power will this bottom end hold safely.
2. Should I get higher compression pistons to go with the alcohol
3. Based on pistion choice and alcohol does anyone have a educated guess on amount of HP this combo should produce.
I know that it is accepted that you should loss 25% HP and Torque through drive line for drag cars, but I am also wondering due to the weight of my truck and the added Transfer casuse. Shouldn't I lose more and maybe that is why my original numbers were so low.
Please help me. I am getting ready to spend a crap load of money in this project and I wan to do it right and also have as much HP and Torque I can get relieablly. I have read many alcohol posts that say they are running 11 to 1 or even higher is some cases with Blown Alcohol engines. If that is static compression, then I am thinking that 7.3 is WAY to low. Especially when you consider some of the posts say that they are running over 20lbs of boost all day. Understand that this truck is still driven on the street some, so I know I am not building an all out race engine, but still want to get as much as I can out of the engine for what my useage is going to be. Limited street, lots of mud and mild trail usage. This is just a big TOY to me. Thanks for your help, if I am stupid or headed completely off base Please don't hesitate to tell me. Tell me the truth. I want to learn the right way, not the Cheap way. Cheap always cost more in the long run.Thanks again
