harold, we had a little discussion on the lsa on blower cams. it seems as if most cam companies recommend a 112-115 lsa. i just picked up a 8-71 BDS blower for a mild street oval port 454. so naturally i'm looking at as many web sites as possible trying to learn something and notice that BDS sells their own blower cams. they are all ground on 110 lsa's for gas. this is from the bds website"

Choosing the proper camshaft would be the most important requirement for a blower motor. An improper cam will cause a variety of problems that can easily be avoided by following a few simple guidelines. Hydraulic cams are recommended if you intend to drive the vehicle frequently, requiring little or no maintenance, and the maximum engine RPM's are kept around 6500 or lower. Roller rocker arms are recommended. Flat tappet and roller cams are recommended for high performance applications especially where the engine will see high RPM's. Exact camshaft specifications vary depending on the performance level you wish to attain. BDS offers ten different types or stages of cam grinds specifically made for blower motors. Refer to camshaft specs listed in tech info for BDS' individual engine camshaft specifications and their intended uses.
If you wish to purchase your cam from one of the many fine camshaft manufacturers, we suggest using our camshaft specs as a guidline. Extremely high lift and long duration cams are recommended for high RPM, high performance racing only.
The lobe center of the cam will play an important role in determining the performance characteristics of an engine. Wide lobe centers (112 to 114 degrees etc.) will create higher cylinder pressure providing more horsepower with cooler burning fuel such as alcohol and methanol. We have found 110° lobe centers to produce the best overall power on gasoline.
Whatever cam you choose, make sure that it will operate and perform properly in the RPM range required for your application

may we ask what YOUR opinion is on this. thanx mike

your motor is a huge step up from my blower motor but the ideals still are the same to keep the motor alive and runner good.

I run a 114LSA summit grind .224/.234@.050 and .465in/.488ex lift with 1.5 crane aluminum rockers.

Car idles pretty well and has instant response. INSTANT. My next cam of choice for a larger blower will be on a 112LSA and 2 sizes bigger in druation/lift. Lots of choices and so many opinions. I hope you get a educated answer from UDHarold but I was looking for him a while back too and got no response. Most say he's very busy which I believe is true. Its actually hard to find a good response for a blower cam recommendation. Theres alot of suggestions of what will work but what truely is recommended..?????...??.?

Blown engines are quite different from unblown ones; clean air and fuel starts entering the combustion chamber as soon as the intake valve cracks off the seat, generally around .001" of valve lift. Unblown engines don't start putting clean air and fuel into an engine until a little while AFTER TFC. Before TDC, the piston is moving upwards and pushing the exhaust gases out the exhaust port, there is no air/fuel intake until after TFC and the piston starting down on the intake stroke.
This is just for blown gas engine, as blown alcohol engines require different cams, as do turbo-charged engines.
Because gas burns HOT, pumping a lot of fuel into the combustion chamber causes a very hot cylinder head, and detonation problems. The more racier blown gas cams are on 108-110 LSA, and use the intake overlap to COOL the combustion chamber down. Needless to say, they don't make that good of a gas mileage. They also have all of the normal actions of tighter LSAs, plus a lot of torque. Tight LSAs don't make good street engines, too snappy.
Wider LSAs make flatter torque curves and deliver better mileage, particularly at lower boosts---6-8 lbs. The blower will add lots of power.
When you get up in real racing blown gas engines, 36 lbs of boost lets you accomplish with 116 LSAs what you used to do at 110 with 8 lbs of boost.
I generally go with wide LSAs on the street with low(6-8 lbs) boost, moving to tighter LSAs (108-110) with higher boosts and racing use, then back to very wide LSAs with very high (24-39 lbs) boosts.
I also tend to pay lots of attention to those who make this their field of expertise.

UDHarold

I always kind of felt that the 110 lsa that BDS recommends for the average street engine was simply for insurance against detonation with pump gas, but really a band aid, and making for a less efficient engine.

thank you for an explanation that even a dummy like me can comprehend!! i appreciate your time. mike