[68bird400HO]

Originally Posted by SD455DJ

Just to continue this fun debate, at the Pure Stock Drags at Mid-Michigan every fall, the best times for the following:

455 HO is 12.76 @ 109 mph (Mark Weymouth's '71 TA optimized to the rules 9.9:1 compression);

RAIV is 12.31 @ 115 mph (Mark Weymouth's '70 Judge optimized to the rules 12.0:1 compression) Bruno is right there as well;

455 SD is 12.57 @ 112 mph (John Glasgo's '73 Formula optimized to the rules 9.9:1 compression);

RAIII is 12.95 @ 108 mph (Todd Kozak's '69 Judge optimized to the rules 12.25:1
compression);

RAII is 11.54 @ 121 mph (Rick Mahoney's '68 Firebird 400 optimized to the rules 12.25:1 compression) Jim Mino is pretty darn close as well at 11.70's, Rick Watson has some 12.10's

RAI is 12.32 @ 116 mph (Jim Mattison's '67 Firebird 400 optimized to the rules 12.25:1 compression)

These are the best et's for each car and usually happened on Saturday morning warm-ups prior to the match-up racing in the afternoon. It seems that most of the HO's, SD's, RAIV's, and RAII's run together in the 12.50 to 12.70 range quite commonly with the few exceptions above, despite the body/chassis type.

Dennis

Interesting comparison. Just to add another dimension, what are the rear end ratios of each of these cars? Also, I thought I saw Dan's Gold T-37 turning 12.50s. What are the specs on his set up (compression and rear end ratio).

[2manyT/A'S]

Originally Posted by 68bird400HO

Interesting comparison. Just to add another dimension, what are the rear end ratios of each of these cars? Also, I thought I saw Dan's Gold T-37 turning 12.50s. What are the specs on his set up (compression and rear end ratio).

Lets add curb weight into the equation,as well......

[68bird400HO]

Originally Posted by 2manyT/A'S

Lets add curb weight into the equation,as well......

True, that is another dimension, but, I bet most of these cars running the faster times are close. I think a bare bones A-body is close in weight to a bare bones F-body (3,500 - 3,600 lbs). The 67-68 birds may be a bit lighter (maybe in the 3,400 lb range) while the SDs are probably a tad heavier. It seems that the RAII/RAIV cars, on top of running 12:1 compression, need to run 4.33s or lower to get those times while the HOs are close with 9.9:1 compression and 3.55s or 3.73s gears.

[bluebird455]

Great read guys, am having a blast reading and learning from all the different opinions and knowledge being shared by all of you. Love knowing some of this cars are being used in such a fun and competitive environment, would really enjoy attending one of the events in the future.
Thanks everyone for sharing your knowledge.

[SD455DJ]

Originally Posted by 68bird400HO

True, that is another dimension, but, I bet most of these cars running the faster times are close. I think a bare bones A-body is close in weight to a bare bones F-body (3,500 - 3,600 lbs). The 67-68 birds may be a bit lighter (maybe in the 3,400 lb range) while the SDs are probably a tad heavier. It seems that the RAII/RAIV cars, on top of running 12:1 compression, need to run 4.33s or lower to get those times while the HOs are close with 9.9:1 compression and 3.55s or 3.73s gears.

We weigh all the cars and list them in the race results. Unfortuanetly, the last two years the track scales weren't calibrated and way off (700 lbs +/- heavy), so left them off the results tally.

The T-37's are in the 3600 - 3700 lb. range, the 69-72 GTO's are in the 3800 - 4000 lb. range, the 1st gen Birds are in the 3400 - 3600 lb. range, and 2nd gen Birds are in the 3700 to 4000 lb. range depending on options, model, and driver girth.

You are correct with the gears, the quickest of the engine types run: 455 HO/SD - 3.73 gears; RAIV - 4.33 gears; RAII - 4.10to 4.33 gears.

Dennis

[Formulajones]

Originally Posted by 68bird400HO

Interesting comparison. Just to add another dimension, what are the rear end ratios of each of these cars? Also, I thought I saw Dan's Gold T-37 turning 12.50s. What are the specs on his set up (compression and rear end ratio).

I'm sure Dan's car is using the max allowable compression, and for an HO that would come in around 9.9:1.
On rearend ratios, You are allowed any gear ratio you want to run. I'm betting he's running about a 3.73 in that car.

[SD455DJ]

Originally Posted by Formulajones

I'm sure Dan's car is using the max allowable compression, and for an HO that would come in around 9.9:1.
On rearend ratios, You are allowed any gear ratio you want to run. I'm betting he's running about a 3.73 in that car.

Dan's Gold T-37 has 3.73 gears, an 068 cam with polylocks to get "0" lash on the lifters, 9.4:1 compression, and weighs 3675 lbs with him and a 1/2 tank of gas. That is with the spare tire and jack assembly in the trunk (nothing but air in the tire). He does have the Hop-Stop bars in the rear suspension. It has the original springs all the way around, and regular duty hydraulic shocks.

We will pull cars to P&G (to check cubic inches) that seem to run too quick and also check their compression ratio with a Whisler (accurtate to within 0.1) box. If the car doesn't pass either one, or both, they can still run for the event, but they have to make the changes to be legal for the next year, because we will check them again. When the event was catching on in popularity 12 years ago or so, we had cars that were blatently cheating (14:1 compression, stroker motors, light weight tranny internals, etc.) that we DQ'd them for teh next event. The F.A.S.T. race was born shortly thereafter. The vacumn minimum check is to keep camshafts from getting out of hand. We can't physically inspect each car for obvious time reasons, but we listen to them idle in neutral and in gear for automatics. We ask that new camshafts be as close to factory original as possible (2% of duration at 0.050" and advertised lift). We used to have a certified class that did a complete teardown and inspection the day before the event and may invite participants who want to prove their cars are legal to do this again if there is suficient interest.

Dennis

[Formulajones]

Originally Posted by SD455DJ

When the event was catching on in popularity 12 years ago or so, we had cars that were blatently cheating (14:1 compression, stroker motors, light weight tranny internals, etc.) that we DQ'd them for teh next event. The F.A.S.T. race was born shortly thereafter.
Dennis

I remember some of this back then. I was a little skeptical of a few of those cars runnng. Glad to see you guys enforce the rules. That group that branched off started their own events and actually have quite a few of them throughout the year at various venues, calling it F.A.S.T. that I touched on earlier in this thread, along with Factory Stock class that is ran much like your Pure Stock event.
So 2 different entities so to speak doing similar things.