Help with blower madness

[Jay Arnold]

Hi , I'm new here and maybe you guys can help me with some issues I have. I'm new to the supercharger thing and need some direction here. I run a '79 ford fairmont with a p600b procharger which is carbureted and not intercooled .I bought the blower used off of E- bay and have made up the rest of the components needed to hang it on the 302. Looks really sweet, love that sound too!! Any how the original 1979 vintage motor lasted one day on the boost !!! Took out three pistons and the head gaskets . O.k., my fault, 13 pounds of boost on cast pistons didn't work out, lesson learned. Two weekend later out with a 1984 5.0 non roller motor all rebuilt with gt 40 heads and 8.5 cr hyperutectic pistons. Ran this motor easy to break it in stayed off the boost etc ,etc. Ran her easy and still after three days ended up cracking a piston and splitting the block wide open. Before I grenade another motor I can't afford I 'll share what will run and and advice or suggestions would be a great help !!!The next motor will be a 306 with gt 40 iron head 7.0:1 comp ross pistons (forged) arp rod and head bolts, 1984 mustang 5.0 aluminum intake manifold, stock 5.0 shorty headers, holley mechaical boost referenced fuel pump, 650 double pumper 76 and 80 jets. Can't remember cam specs exactly but 480 lift and 230 duration are ball park(non roller).Iwill be installing a custom made blower pulley to tame the boost down from the insane levels I was seeing.Timing was at 25 degress total on duraspark ignition.As you see this is a budget buildup and the cash cow has ran dry for this year. anything I can do to make this motor live would be a great help, as I'm obviously missing something here ,Help!

[Black01GT]

since your getting forged pistons, i would go with at least 8.5 or 9.0:1 compression pistons. ive got 9.0:1 probe pistons on my car. ditch the stock 5.0 headers for a set of MAC unequal length shorties. and when picking a cam, the lift looks fine, just make sure it has as little over lap so you dont lose boost out your exhaust!

[Slush]

hrmmmmmmmmmm..... Well you are on the right path, and I understand when you have to do a budget rebuild. I would say you wouldn't have to go as low as 7.0:1 compression it might be a little more sluggish out of the boost, I would think you can be safe at 8.5:1. I am currently running 8.9:1 on a blower motor and so far so good. The iron heads don't dissapate heat as fast as aluminum heads but, with a budget rebuild I know that cost is a factor. Also while doing the ARP head and rod bolts might as well do good main bolts, ARP main bolt kit is ~18 bucks. How high are you spinning this motor, and how are you making sure you are getting enough fuel?

[Jay Arnold]

I was spinning my first motor to 6700 without the blower on it. Since the blower went on 4000 has been tops for any of the two motors. Boost goes too high and I have to let up on the throttle. Never had enough time to sort this problem out as the pistons would give up first :(

[IUP99snake]

i highly recommend that you get fuel injection and a chip. it doesent really matter if its the stone-stock 5.0 parts (except for an upgraded fuel system) for now, just as long as you get it fuel-injected. itll be 10 times less finicky than that carburetor.

8.5:1 pistons should hold at least 15-20 lbs of boost safely.

-Homer

[Jericho574]

You tell him Homer!