Projects Northwest Vintage Dragster Group Build.

And here's what's needed to be done on the block:

http://www.customdesignperformance.com/leo/block.html

 

Spacing back the converter from the flexplate does make sense. Maybe gluing the spacers to either the flexplate or converter. My mind goes right too the frustration of getting them all in there loose.....i see wrenches thrown threw windows lol

 

A few days ago i recieved a cool pm, and asked permission to post it here as I really got a kick out of it. The message came from pete1,

Hi,
I just came across this thread.
What you are doing is neat stuff but a little later vintage than I imagined from the title of the thread.
A friend and I built the first thing that could be called a "dragster" in the NW in 1951.
It was basically just a frame with a 315 ci flathead in it. No body at all.
At the time, we figured if we were strapped in tight and had a roll bar, we were safe...LOL
They had no elapsed time clocks at that time so MPH was all we had.
The best we turned was 128 on straight alcohol.
We experimented with Hydrazine and Picric acid but all we got was more wheel spin.
We ran at the old Arlington,Wa airstrip.

I see Marty Strode is on the thread also. He is a very good friend of mine and I have raced vintage circle track roadsters with him many times.
Pete Samuelson

 

Leave the flexplate and starter in place as GM designed them. Have the converter built for the mid plate thickness. This is common race car build for performance converters. The converter pilot hub for the crank shaft must be extended for proper alignment of the converter between the engine and transmission

 

I do think that is probably the best way to go however we are building a dragster to go 12 seconds, really a cheap thrills kind of thing. It's probably going to get either the fexplate spaced out or the converter spaced back. The converter seems like the best option in my mind as a little thickness variation out at the converter bolts will make a lot less difference than a little thickness variation at the flexplate bolts.

Either way we are probably overthinking it on something that probably wont see 5000 rpm. I would bet either way will work and likely if no spacers were used and the converter was run slid out of the pump .090" it would likely still be o.k.

 

I have a home built high 11 second dragster and used the stock motor mount locations. No midplate.

 

That was our first plan, but making the midplate was pretty easy on the plasma cam and as some of the previous posters advised it should make it easier to seal up the cockpit.

 

You guys are putting in the right kind of effort, to get these cars started off in the right direction.


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Pete is good old boy, built a 325" injected Flathead, the most ferocious Flathead I have ever heard ! He knows his way around a cam grinder too !

 

Pizza and apple pie got us off to a good start last night.


While it isn't a full new midplate as suggested, one of us forgot to pick up more cold rolled this week (shit that was me) so we collectively decided to save the one we made last week by cutting filler panels that will also serve as the mounting tabs. It will have a row of button head cap screws around the perimeter. It definatly won't be as handy when pulling the motor but I don't think we will be going that deep between rounds.

The tabs are drilled for the mounting bolts seen in this next picture, but we havent gotten around to drilling the midplate yet.




We reworked the front mount and made up some tabs for it.

 

Last night wasn't super productive, a lot of head scratching on the floor l, driveline enclosure, axle anti-rotation and seat but I think we have it mostly thought threw.

We did knock out the bar that goes over the knees and the start of the floorboards.




I cought Randy taking it for a spin!

 

The front tires made an appearance yesterday

 

Looks great. Thanks for the updates.

 

Looking good gentlemen, great work. Everything is coming together nicely ,love the firewall and floorboards. You could almost drive it as is,almost.


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Walt, do you happen to have any pictures/advice of how you handled the seat and seatbelt mounting? I have this harness that should be here for build night this week

 

The lap belt should cross your hip bone as it heads towards the frame--usually about a 45 degree angle. The shoulder belt mounts should be below your shoulder but not excessively so. That is, they should hold you down a little as well as back. In your type of car it is usually a good idea to run the belts over a tube and then down to the mounting point. It looks as if you have "pull down" lap belt adjusters which will probably work OK in your application due to the width of the chassis but "pull up" is usually better in narrow cars.

http://www.sfifoundation.com/wp-content/pdfs/guidelines-bulletins/Seatbelt Installation Guide 06-05-12.pdf

Roo

 

And a few years ago NHRA specified separated mounts for the shoulder belts, can't mount'em together any more.

 

mine are wrapped around frame tubing at the shoulder hoop and the rest are clipped to eye bolts inline with your bung for crotch belt an just inside the lower frame rail for the lap belts I have the same belts and I just removed the shoulder clips and reterminated the belt with supplied h clips

 

This is how we do it at our shop.When we build a car, we build it for the driver. As stated above the lap belts usually go at about a 45 degree angle, mounted to the floor at the backside of the seat. The shoulder belt should be at least 4 inches below the top of the drivers shoulders, no lower than 6 inches. The crotch belt should mount to the floor at a point that is behind the drivers chest line. We try to use the double crotch belt which mounts to the same points as the lap belts. When using the wrap around belts, be sure they cannot come in contact with the track surface in case of a crash, such as on the lower frame rail

 

Rob - Regarding Seat & Belt Mount. I'm not much of a tin-bender, so I tend to make straight flat panels. And since we're not trying to remove the last ounce of weight on these cars, I use a separate seat w/upholstery. I like to be able to comfortable enough in the seat to be able to take a nap while waiting in the staging lanes. So here goes:

I like to use a Kirkey 41 Series Pro Street Drag seat & Upholstery. Nice seat & comes in various widths. I did have to trim off the headrest to fit my chassis.

I welded cross bars in the chassis with mounting tabs to mount the seat:



My seat belt mounts are just flat plates welded to the cage uprights slightly angled in. Hard to distinguish in this picture, but there are there:



The shoulder belt mounts are just threaded bungs welded to the back vertical chassis bars. Using the vertical bars allow you to place the mounts far enough down to meet the rules. I use threaded tube ends like used on linkage bars.



I cover the floor under the seat and mount the seat with "L" brackets on the bottom and a back brace:





To enclose the rear section of the chassis I used 3 flat panels. The interior one shown above, and the side panels on the outside. You can also see the rear end anti-rotation bracket:



And that's about it. I have started using clevises instead of a flat plate to mount seat belts. Drill one side for bolt clearance and thread the other side. Puts the bolt in double shear and only one wrench needed to tighten.



Hope you find some of this useful.

 

A&A makes a nice double shear belt mount among a large selection other useful tabs.

 

Casual Six, I see a bit of the pumpkin showing through the floor boards. I thought, maybe mistakenly, that a shield was required over the rear end. I like your shield for the driveshaft, very simple and effective. Here is our rear
end shield and the rear part of our driveshaft hoop.
Warren

 

Cool build .... I was going threw some old magazines my brother give me and run across this one .... Thought the rail looked like what you guys are putting together.....Looks like it will be alot of fun....

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Warren,
that fits into the category of overkill. The rules require some sort of device (apart from the housing mounts themselves) to prevent the rear end from rotating and possibly beating up on some seriously sensitive areas of the driver's body. Also required is some sort of shield over the u-joint/coupler (for the same reason).
A common method of handling the anti rotation bracket requirement with a 9" rear end is to mount a plate to the pinion support bolts that attaches to a cross member. The driveshaft cover can also be attached to that plate. What you have will work but it makes servicing the rear end difficult.

Roo

 

Thanks for all the replies, gives us a lot of options. I'll try to take more pictures as we go along this week.

Hmm wonder what wil be for dinner.....lol

 

Warren - Yes, there is a small odd shaped piece to cover that. Just didn't have a picture.

Nice fab work on your u-joint shield, but where does the anti-rotation part attach to the rear axle?

 

Not to steal this excellent thread, but it has been mentioned twice. At first with the rear end mounts and the pumpkin cover, it was felt that an anti rotation device wasn't necessary, but that all changed in the planning conversation last night. It will be there.

Warren

 

Any idea when you will be in Spokane?

 

Nothing better than an old Bridgeport! !