CLASS RACER FORUM - View Single Post - Project - NHRA Stock and S/S results 61-68

oldskool · 11-05-2021, 01:39 AM

"...Dwight said the RA2=385hp factored by NHRA...

I think the RA4 was at 380hp all thru because there are RA4 cars in the wins/records from early 1969 thru late 1970 that all fit 380hp..."

I find that REAL interesting.

WHY ?

Because the '69 RA4 had the same cam, BUT, the RA4 used 1.65 ratio rockers, whereas the RA2 only had 1.5 rockers. This gave that engine more valve lift & more effective duration, which HAD to produce more power.

THEREFORE, why would NHRA actually rate the RA2 engine higher ? Don't make any common sense.

http://www.classracerinfo.com/Engine...3&MAKE=Pontiac

http://www.classracerinfo.com/Engine...2&MAKE=Pontiac

Don't think it actually increased power output, but the RA4 also had an alum intake. Seems that NHRA would have taken this into consideration & initially given the RA4 a slightly higher hp factor. or at the very least, the same as the RA2. Can't think of a single reason to rate the RA4 LESS than the RA2.

The answer to WHY, would be very interesting to me.

AND, after a few '69 Judge Stockers began setting records & winning class at some races, seems that NHRA would have taken another look at the RA4 engine & upped the hp factor.

"...???? 1972..."

Yeah, I think I posted a pic of Truman Fields running A/S @ the Summer Nats, in '72. So, that was a special year. Seems that Stock had sort of "Pure Stock" rules that year. I suppose the weight breaks were different, which caused Truman's Bird to run A/S. He even set an A/S record.

http://classracer.com/classforum/showthread.php?t=51198

Then, '73 was the year Truman won Stock @ Indy, running C/S. Then, in '77, Mike McKinney won Stock @ Indy, running that same car, in B/S. Lots of rules changes back in those days.

Pic #7 shows Truman running in D/S. Don't know what year that was.

He ran '68 Birds with several different paint schemes. Pic #8 shows one of 'em, with B/S on it. Also have a pic of it that color, running C/S.

Pic #9 shows a Burgundy color he ran, in D/S. So, these pics show Truman Birds in 3 color schemes & 4 different classes. He also moved several times, as noted by the different perm numbers.

11-05-2021, 01:39 AM	#196
oldskool VIP Member Join Date: Dec 2014 Location: The Land of Bayous, Boudin & Crawfish Posts: 1,668 Likes: 223 Liked 750 Times in 361 Posts	Re: Project - NHRA Stock and S/S results 61-68 "...Dwight said the RA2=385hp factored by NHRA... I think the RA4 was at 380hp all thru because there are RA4 cars in the wins/records from early 1969 thru late 1970 that all fit 380hp..." I find that REAL interesting. WHY ? Because the '69 RA4 had the same cam, BUT, the RA4 used 1.65 ratio rockers, whereas the RA2 only had 1.5 rockers. This gave that engine more valve lift & more effective duration, which HAD to produce more power. THEREFORE, why would NHRA actually rate the RA2 engine higher ? Don't make any common sense. http://www.classracerinfo.com/Engine...3&MAKE=Pontiac http://www.classracerinfo.com/Engine...2&MAKE=Pontiac Don't think it actually increased power output, but the RA4 also had an alum intake. Seems that NHRA would have taken this into consideration & initially given the RA4 a slightly higher hp factor. or at the very least, the same as the RA2. Can't think of a single reason to rate the RA4 LESS than the RA2. The answer to WHY, would be very interesting to me. AND, after a few '69 Judge Stockers began setting records & winning class at some races, seems that NHRA would have taken another look at the RA4 engine & upped the hp factor. "...???? 1972..." Yeah, I think I posted a pic of Truman Fields running A/S @ the Summer Nats, in '72. So, that was a special year. Seems that Stock had sort of "Pure Stock" rules that year. I suppose the weight breaks were different, which caused Truman's Bird to run A/S. He even set an A/S record. http://classracer.com/classforum/showthread.php?t=51198 Then, '73 was the year Truman won Stock @ Indy, running C/S. Then, in '77, Mike McKinney won Stock @ Indy, running that same car, in B/S. Lots of rules changes back in those days. Pic #7 shows Truman running in D/S. Don't know what year that was. He ran '68 Birds with several different paint schemes. Pic #8 shows one of 'em, with B/S on it. Also have a pic of it that color, running C/S. Pic #9 shows a Burgundy color he ran, in D/S. So, these pics show Truman Birds in 3 color schemes & 4 different classes. He also moved several times, as noted by the different perm numbers. Attached Thumbnails Last edited by oldskool; 11-07-2021 at 09:00 AM.