About Us

nitrousdave · 09-29-2005, 10:19 PM

HI GUYS, I AM NEW TO THE BOARD, BUT I WOULD LIKE SOME ADVICE ON WHAT YOU THINK ABOUT MY CURRENT BLOWN BUILD-UP ON MY 400 PONTIAC IN MY 75 FORMULA. HERES THES SPECS: 400 .030 OVER FORGED PISTONS, STOCK CRANK,CROWER CAM, .507 LIFT INTAKE AND EXHAUST 242 AT .050 110 DEGREE LOBE SEPARTION. PORTED 6X-8 HEADS 6-71 BLOWER WITH 2 EDELBROCK CARBS 750 CFM. HOOKER HEADERS, AND 3 INCH EXHAUST. LET ME KNOW WHAT YOU THINK. AND WHAT KIND OF POWER I COULD EXPECT.

Mo · 09-29-2005, 11:29 PM

You chose the right place to get some help. If you haven't already tried, you can try to SEARCH for some past posts on blower set-ups. Lots of guys with blower motors. I'm no expert BUT the cam seems to be more for a N/A motor. Is it? How much boost are you planning?

Bill Bolin · 09-30-2005, 11:16 PM

Dave...I second the cam concerns. I run a 116CL on my blower cam. I also tried the Edelbrock carbs and they were junk IMO. I now run the Holley 750 Supercharger series carbs with the boost reference already built in. They work great!! If you want specific questions answered, you can Email me at [email protected] . Looking forward to another boosted Pontiac!

73FIREBIRD · 10-01-2005, 12:39 AM

I just fired my 440 with an 8/71 blower to night. The 110 center line on yours is not the hot set up for a blower. needs to be 114 or 116 the 110 will cost you some hp Don't know about the edlebrock carbs but if pontiac462 says they are junk I would believe him. I also run two 750's but are Barry Grants with the boost referencing in them. What is your static compression set at. With the iron heads it needs the be at 7.5 to 8 to 1. What kind of rods are you going to run? Also I wouldn't go any more then about 6 or 8 lbs of boost if you will be driving it on the street. Make sure you have a good fuel system on it or you will go lean witch will kill it in a heart beat. Keep us posted on how it is coming

Jack Gifford · 10-01-2005, 12:44 AM

I hope you follow through on this, and have loads of fun!
I had no complaints about an old-school N/A grind in my blown 400. But that was competition-only on alcohol, with mild boost, about 12 PSI. For street-gasoline use, I think I'd pick the brains of everybody I could- all the major cam companies, and of course all the members of these forums.

nitrousdave · 10-01-2005, 05:57 PM

THANKS, GUYS I APPRECIATE ALL THE ADVICE , BUT I WAS WONDERING WHY ALL OF BDS BLOWER CAMS HAVE 110 DEGREE LOBE SEPERATION ANGLE? I WILL CHANGE THE CAM IF I HAVE TOO, BUT I WOULD LIKE TO TRY THIS CAM, AND SEE HOW IT RESPONDS. ALSO WHAT IS WRONG WITH THE EDELBROCK CARBS? I HAVE SEEN SOME BLOWER SETUPS WTIH THEM AND TALKED TO A FEW PEOPLE. AND THEY HAVE HAD GOOD RESULTS, AGAIN I WILL CHANGE THEM IF NECESSARY. BUT I WOULD LIKE SOME MORE ANSWERS. THANKS.

Tom Vaught · 10-01-2005, 07:01 PM

Most generic Chebby cams are ground on 110 lobe separation.
Offering the same profile on a Pontiac camshaft simplifies the profile
choices even though the cam may not be the best one for a Traditional Pontiac engine. JMO

Tom V.

Bill Bolin · 10-01-2005, 09:26 PM

I had the Edelbrock 1407 carbs on my "other" motor (BBC). They would idle fine and drive OK but wide open throttle was pitiful. When I changed the carbs to 660 center squirters, the car woke up. It was like adding nitrous. The EGT also dropped .Most cars that you see Edelbrock or Carter carbs on are pure drivers, not much as far as performance goes. The Holley carbs are easier to tune for most people. The Holley 80573-S carbs are what I have now and they idle well, drive well and when I get on it hard....they give excellent results.

Your car will run fine with the Edelbrocks but if you tried the Holleys, you would never go back to the Edelbrocks. If you already have them, use them. Just start saving money for the Holleys.

nitrousdave · 10-01-2005, 09:34 PM

SO TOM, YOU ARE SAYING THAT MY ENGINE WILL NOT RUN THE BEST WITH MY 110 DEGREE LOBE SEPERATION ANGLE CAM? 73 FIREBIRD, THE COMPRESSION ON MY ENGINE WILL BE 8:1, I FEEL LIKE THIS SHOULD WORK WITH PUMP GAS AND A BLOWER. ALSO I HAVE EAGLE RODS IN MY ENGINE, ALONG WITH PORTED 6X-8 HEADS WITH 2.11 AND 1.66 EXHAUST VALVES, THE HEADS FLOW AROUND 240 CFM AT .550 LIFT. SO GUYS WHAT DO THINK THIS COMBINATION WILL MAKE AS FAR AS HORSEPOWER? AND TORQUE? I AM LOOKING TO PUT THE 75 BIRD INTO THE 10 SECOND ZONE, YET STILL REMAIN STREETABLE ENOUGH TO DRIVE. THANKS.

Torment · 10-01-2005, 09:50 PM

BDS puts out all their street blower cams for Pontiac's on 110's, the theory being it keeps the heat down a bit cruising. I've run a couple and they ran hard. I've found 8.5:1 static to work well with my iron head combination. At 8:1 I was able to get away with 6-7psi boost on 93 octane and 25 degrees total timing. My current cam is on a 112 and the performance is adequate. I run 2 old 850DP Holley's scabbed together with spare parts. They're not boost referenced or 'curved' for a blower but they seem to work well. Make sure you have plenty of fuel and lots of initial advance - I run mine locked out at 25deg. They get hot in a hurry otherwise. If you run into head gasket troubles get a set of Cometics, they work slick.

nitrousdave · 10-01-2005, 09:53 PM

HEY, TORMENT WOULD YOU BE SO KIND AS TO SHARE YOUR COMBINATION WITH ME?

Torment · 10-01-2005, 10:11 PM

Mostly...
455 .030, stock crank, mains, bolts, Eagle rods, Ross pistons, 614's, ARP studs, 270ish Isky solid, BDS 8-71, (2) 850 Holley, single point w/Pertronix & MSD, NOS intercooler.
74 Firebird, TH400, 9" TCI, Dana w/3.73's.

Flamin65 · 10-01-2005, 10:40 PM

Here is a picture of the carbs I'm using on my 6-71. When I get done they will be 750 Dominators because some nice guy on here showed me how to change them over. (I still owe him some money for the help when I see him next time though) because noone helps for free. LOL

Greg

Flamin65 · 10-01-2005, 10:46 PM

Sorry one more picture

nitrousdave · 10-01-2005, 11:03 PM

WOW! GREAT LOOKING SET-UP FLAMING 65. WHAT KIND OF COMBINATION ARE YOU RUNNING,AND ARE PLANNING TO RACE YOUR CAR? HEY TORMENT, WHAT KIND OF TIMES DOES YOUR CAR RUN, AND IS IT ALL MOTOR OR DO YOU SQUIRT A LITTLE NITROUS?

Formulas · 10-01-2005, 11:13 PM

The theory with the 110 vrs 112 LDA and beyond is when both valves are open your blowing fresh intake charge through the cylinder more on the 110 than on 114.
You cant begin to pack a cylinder until the exhaust is closed.
I have never run a blower but if i was trying to keep the heat down might consider a wider seperation with slightly lower intake PSI rather than waste a intake charge blowing through a cylinder to keep it cool.. just a opinion.

Torment · 10-02-2005, 10:44 PM

9.88 on motor, 9.37 with an NOS intercooler. It'd go 9 teens but my 60's get worse with the NOS - traction limited.... 3750lbs with me in it and 5gal of fuel.

nitrousdave · 10-02-2005, 11:34 PM

TORMENT, THOSE ARE FANTATIC NUMBERS! NOW WHEN YOU SAY INTERCOOLER ARE YOU REFERING TO THE 6-71 KIT THAT NOS MAKES AND SELLS AT SUMMITT OR JEGS? ALSO YOU STATED THAT YOU RUN RAIV HEADS, ARE THEY STOCK OR ARE THEY PORTED? SORRY FOR ALL THE QUESTIONS, BUT I WOULD LIKE TO BUILD AN ENGINE LIKE YOURS IN THE FUTURE AND I AM TRYIN TO GET ALL THE INFO I CAN. ALSO DO THINK MY CURRENT COMBINATION THAT I AM RUNNING WILL BE ENOUGH POWER TO GET IN THE 10 SECOND ZONE IF I HAVE IT SET UP PROPERLY. THANKS DAVID.

Torment · 10-03-2005, 09:57 AM

I run nitrous oxide by NOS (company brand name) as an intercooler - power booster sprayed in under the carbs before the rotors. The IV's are ported a bit but I've run Dports as well with very good performance - I don't think a well setup Dport like the 6X's you mentioned would hold you back from attaining same/similar/better performance than I am. I simply ended up with the IV's through a parts trading scenario.

As far as performance your setup is a bit different from mine but, assuming the 6-71 is in good shape I think it would be attainable. I think it'd be pretty tough to get there on pump gas and 6-7psi though. I ran 10.3's with a 255deg solid on a 110lsa, Dports, and 11-12psi boost back a few years. Maybe it would have went 10.8-9's on pump, don't know I never ran it that way at the track - only on the street. Can't comment on your carbs as limiters - no experience, I've only run the Holleys with the blower. I've had friends that have run them for short periods of time and got rid of them soooo....maybe lack of our knowledge, maybe lack of carb ability, maybe both.

The right converter makes a big difference on the track if you want that 10sec et, on the street it's not much of an issue - consult your favorite company. Proper initial and total timing is very important. For benchmark tuning purposed I'll tell you I run 25deg total and locked out. Don't run a wide curve, if you get under 18deg initial (idle) I've found they tend to get hot quickly. Don't restrict your air inlet, and don't restrict your exhaust - either will make it a slug. Spend a little time finding the right jetting either at the track or on a dyno.

Maybe more advice than you're looking for, but hopefully some of it saves you some time and gets you up and running quicker.

Torment · 10-03-2005, 10:03 AM

Oh, and run lots of radiator, a good water pump, and a big fan. You now own a bonafide furnace.

Formulas, I wouldn't disagree at all - that is exactly it, blowing the cylinder down.

Menu

About Us