I'm building a 255ci (french) flathead engine where i will fit a 4-71 blower on top. All porting is done.Manley pro flo valves to be used. To learn more about blowers i bought Pat G. supercharger book. Is has a article about cam selection in it. There you should rather have a cam with more exhaust duration than intake.... Some guys here run the L-100 with a blower, which has the opposite pattern. I read the blown flathead book , too..... he only suggests either Max1 or 400jr. Cheaters Pete has a strong running blown flathead witha Max1 I thought about a L-100 until i read the supercharger book. I will have a cam regrind anyway so i can choos any pattern. And no i didn't call any cam grinder as it is Sunday today ) TIA Michael
Mike... Flatoz and I run the L100 and they runs real good. But having said that,I believe custom blower cams are a better option too and they being ground Stateside by Tatom and a few others. I also believe Schneider and a few smaller grinders (Cam Techniques?) will grind you a cam to your spex as well... Blower engines tend to like wider lobe centers, say aroud 112-114 deg of lobe sep. Whilst this is true for most overheads, Im also pretty sure that it applies to Flatheads as well and I was thinking of swapping out my L100 for a custom blower cam with not too much duration @.050" , more lift on the exhaust side and more intake lift to let her breathe along with that wider lobe sep to prevent boost going out the exhaust. Perhaps Flatdog can enlighten us some more as to the cam spex as hes got his blown Flathead running REAL hard in his 34. Joe Abbin might be another one to talk to - he has built some pretty hard running blown flatheads although I believe he generally sticks to Isky 400 Jnr cams which have lots of lift, and a smaller duration @.050" so they dont bleed off too much cyl pressure, but I don't know what kinds lobe sep they have. Jump in, blown flathead brothers !! Rat
Joe Abbins done a lot of dyno testing and I belierve his highest HP figures were with the Max 1 cam. I have a 400JR in mine cause it was in there before I installed the blower. The 400JR has a lumpier idle than the Max 1 though so I guess it's somewhat what you really want as a good ALL AROUND cam.
I'm running a 400jr in my Abbin blown sedan and it has been trouble free for over 9000 miles.Very streetable. Running 5spd behind it with 350 rear ratio. Would highly recommend this setup. Google Joe's website at Roadrunner engineering and then give him a call. Just a terrific guy who will be glad to answer all your questions. He'll talk your ear off.
Joe's latest engine has a 400JR cam in it - over 300HP with his blower, Offy heads, some porting & head work...running mid 12s
Well here is my story.Not sure but this what happened motor is 3 5/16 by 4 3/8 cam is a Crowler roller it was never ment for a blower.It was ordered as a hot street cam.It did not outperform a MCF 7/8 grind.I kept trying diff manifolds trying to inprove performance with no success.Brought blower set up 5 years ago my kid want to put right on car.So I let him car CAME alive got to 12.91 @ 3200 lbs.At this point I started to studdy cams for next motor.I did not use cam card spect.took cam #s off degree wheel on crank.Here is what I found my Crower looked like a L-100 with more lift. (I am trusting book L 100 specs.)Known guys run max 1 400 jr l-100 all sucessfully it does not suprize me . Think all would work well.FWIW took street motor out of coupe because altered motor broke street motor with 5 years street use on it goes 10.50 125 in altered.
Ok , update . i talked to a cam grinder in So-Cal and he suggested a 270° , 114° lobe, 0,395 lift cam. Sounds good to me !!! I will order it. Michael
Michael this is an AWESOME book on flathead engines. These guys build some serious flat motors and they are VERY forthcoming with info in the book, hundreds of colour photo's, VERY specifc part numbers and sources of everything involved plus complete rebuild instructions. They go through complete builds of 3 motors in this book a) 1946-1948 Model 59 Flathead b)1962-1990 blown SIMCA of France flathead (GMC 4-71) c)Blown Ardun flathead conversion Cam selection paragraph reads "Crower Cams & Equiptment Company reccomends the SPL8BA blower grind custom flat tappet (lifter) camshaft for the French Flathead V-8 engine. This camshaft has an advertised duration of 277 degrees intake and exhaust; duration at 0.050-inch lift:224 degrees intake and exhaust; lobe seperation angle: 112 degrees; net valve lift: 0.321-inch intake and 0.012-inch exhaust. This is a terrific street blower camshaft, and price is with no core exchange"
Hi !!! Thanks for the tip on the book. I'll buy it. I let you guys now what i will order. Anybody needs a L-100 in Europe? Michael
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