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Author Topic: Attaching sub-assemblies to the "frame"  (Read 3158 times)

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Offline RebekahsZ

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Attaching sub-assemblies to the "frame"
« on: December 10, 2016, 09:38:22 PM »
I have purchased an unfinished 1931 Ford chopped hi-boy coupe and I am finishing the car up.  While the car will primarily be a street-driven hot rod, I DO care about safety, and I think this forum might be the most safety-oriented forum for hot rodders, so I pose my question here and hope that you fellas can guide me.  While the car will be primarily street-driven, I do hope to at least compete to 135mph with the ECTA and I will be doing some bracket drag racing and vintage drag racing and maybe Drag Week, expecting the car to run somewhere in the 6s in the 1/8-mile.

I need to mount the fuel tank and the battery in the trunk.  The battery will be in an NHRA-approved and vented metal box.  The fuel filler cap will be outside of the trunk between the b-pillar and the rear deck lid.  We have welded 14 gauge steel floor pans to the body rails and body crossmembers.  Most rule books suggest that these heavy items (tank and battery) be attached to the "frame."  As I see the construction of these old coupes, there are actually 2 "frames:" the chassis rails and the body rails (a boxed section of the floor pans).  These items are mounted to the unibody in my unibody Modified Sports race car, and the body rails of the hot rod are AT LEAST as solid and strong as that unibody (and probably stronger)!  Do you fellas think that mounting these items solidly to the reinforced body rails will be adequately safe for my stated level of performance plans?  And pass an NHRA inspection?

Offline oj

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Re: Attaching sub-assemblies to the "frame"
« Reply #1 on: December 11, 2016, 09:04:49 AM »
No.  I can't speak for ECTA but NHRA is very clear, they want the fuel cell & battery going to the frame.  You don't need a battery box of you have a bulkhead seperating trunk & drivers' compartment.  At one time they were very clear they wanted 1/2" bolts to secure battery but I've never seen it in the book and they may have eased that requirement, best check with NHRA before welding stuff.

Offline jimmy six

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Re: Attaching sub-assemblies to the "frame"
« Reply #2 on: January 03, 2017, 08:38:29 PM »
Always follow the rules of the organization you are planning to compete within. The SCTA rule book always has  been considered to meet the minimum requirements to run. The SCTA is not the NHRA even tho some requirements are very similar.
 As an example my roadsters battery is attached to a 3/16" steel plate which is bolted to the bottom of my frame rails in front of the engine and behind the grille shell. I do not care if it meets any NHRA spec as I am never going to compete at a drag race.
First GMC 6 powered Fuel roadster over 200, with 2 red hats. Pit crew for Patrick Tone's Super Stock #49 Camaro