I have been helping an old friend with a gasser chassis build. While I have lost or misplaced my 1968 rule book I was sure a gasser was allowed no more then a 10% engine setback location as measured so that the distance from the centerline of the front axle to the #1 or most forward sparkplug hole cannot be anymore then 10% of the wheelbase. IE on a 94 inch wheelbase the front sparkplug can be no more then 9.4 inches behind the centerline of the front axle. My friend keeps saying that is an altered and I think some folks who werent there back in the day are poisioning his mind with misinformation. A similar car with engine in stock location would not be a Gasser but Modified Production as in A/MP B/MP C/MP etc. An Altered can have up to a 25% engine setback as I recall. He is about to re do his whole chassis over this but before he ruins a beautiful piece of work could someone please quote the actual rule from the old NHRA rulebook. He has the car now as a a roller. Maybe my mind is going but I spent 2 years as a Techer at Mohawk working under Div 1 tech guy Walter Doyle when it was NHRA so I hope I am not losing my marbles. Don I am also working on one myself so I should straighten this out right now.
10% for gasser, i don't think there is any limit on an altered. After the 'gas' and 'altered' classes were combined any engine setback is allowed. But when 'gas' was a seperate class within comp eliminator it was 10%. When i was building my first tube chassis car i was building it to B/G rules and that was the year they combined 'gas' and 'altered' and i had to do some serious re-engineering and i tried to run B/A. I could qualify but never was competitive, a door car just don't stand a chance against a true altered.
I cannot quote a NHRA rule book as I misplaced mine eons ago but you are correct about the 10% set back for gassers and 25% for altereds. That was the standard for ages.
I recall the 10% rule was measured from the centerline of the left front spindle--to the centerline of the #1 sparkplug. 25% was for altered. Ohio George's Malco mustang was set up with 2 different length front ends that simply bolted on , shorty for gas class , stretch for altered / FX .
I just looked at my 64 NHRA Rule book "Engine may be relocated, but not to exceed 10% of the wheelbase as measured from the centerline of the front spindles to the nearest spark plug hole. Engines may not be raised more than 24" from the ground, measured from the centerline of the front crank pulley to the ground." My 71 NHRA rule book says the exact same thing 67 AHRA rule book is the same except they just use the word Excessive when reffering to raised engine height.
Just bumped the rules to the top for you. He can read them himself if he wants. http://www.jalopyjournal.com/forum/showthread.php?t=334715
Yes Sir, You do, But that is what I recall also, The rules on that didn't change for years, around early 60s until they restructured the class in the 70s. We built a couple early corvettes for /MP because of the factory setback, and some other benefit's over the 55-57 Chevy that we had run in Gas class for years. But like you said the alters setback of 25%.That put the motor into the drivers compartment, cutting up the firewall and that was the start of the AFX cars and then on to the first funny cars. I will continue looking for our early rule book, My Buddy has a large car collection and parts. thx
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