I'm Gonna Build A Dragster!

[soltz]

Nice work [[ [cl
I found the electric die grinder work better than air also, it took 5 yrs to wear out my first H.F. unit and the new ones are a little better [cl

 

[smallfoot]

Yeah, it has been kinda misty this am...

 

[old28]

Ya Bob that intake/exhaust flange with your dual 4bbl intake and a true header exhaust with the right size pipes & collectors will for sure help you get into the 10's. When I added my home build "junk" 6 into 1 collector I went from 12.29 to 12.05, nice improvement for my small 194" motor. I am sure I could have ran 1/2 second better with the right size pipes & collectors. With your intake, carbs & better flowing exhaust system it is looking more like an aggressive cam change is in your future. Next season will tell.[cl

 

[bob w]

Yes, old28, probably needs more cam. But this go round the present cam remains.

Finished gasket matching the intake manifold and the flange plate. Pulled the head and after 5-6 years of racing it looks good. Piston tops too.
Notice the mismatch between the flange plate, which is gasket matched, and the ports in the head. cold be some lost ponies there.

 

[old28]

Bob, Ya that head ( valves & chambers look nice, how many passes on it?

I'm with you, get out your die grinder and clean up those ports, I'm sure there are a few ponies there. Easy fix that you can do at home.

I would do as you are on mods and when you have got all you can from the current setup then it's time for a cam change. You got to be close to a high 10's with this current setup.[cl When is your first race in 2023?

 

[bob w]

The new header for the dragster arrived. Cut and weld to fit. haha.

I keep watching porting videos but I think I'm about 90% done with the head.

Tom, there's about 50 passes on the head. The block will go to the shop to get the deck milled more. Trying for .040" quench. The tops of the pistons will be slightly above the block.

Forgot to mention, a couple months ago I relocated the battery box forward a bout 10". Before, it hung out the back like a big cement block. Now it's tucked within the cage.

Began tearing it down to the bare frame last night. See what I can cut out of it for weight reduction. Will try to pretty it up. We have tentatively been invited to a cackle fest during the NHRA meet in Brainerd.

Will probably go to Test and Tune in May to see if the thing performs better. I'll hang up my wrenches and quit if it doesn't.

 

[bob w]

She's looking pretty naked.
I checked the piston to deck height & it varies from hole to hole. Not much can be cut from the block. Maybe .004". Don't know if it is worth the work. Can't find what HP gain would result.

 

[kenny c]

It would be an awful lot of work for just .004". Did you take into account for compressed thickness of the head gasket?[P

 

[oneeye]

[

 

[old28]

Bob, she does look real bare. Does anyone make a Copper Head Gasket for that 300 motor? With the compassion head gasket in the .035 range & most copper head gaskets in the .015-.020 range you might pick up .015 - .020". Would increase the compression ratio a little. .004" at the machine shop is a waste of money.

If you are going to stay with the cam you have you might think about running a set of BBC 1.75 roller rockers. I tested a set on the 300 motor I was building. They will be a bit off center on the valve stem tops but will be fine for a drag race motor at 5700 rpm's & 20-30 passes per year. Next best thing to a cam change.

Keep the faith, "10.99 or better", then you can hang up the wrenches.
You know it can do it, just needs a little less weight & a bit more power. Get it done. Good testing.

 

[bob w]

Kenny, I measured the compressed thickness of the used head gasket. It's ideal quench I'm after, .004" would put me in the ball park. One gauge of bad quench is carbon/soot on the piston tops in the quench area. The pistons in this engine are very clean in that area so I'm leaving it alone.

Tom, a cam is probably the right decision but I hate to move the power curve up and give up anything at 3,500 rpm. That's where it launches. As far as I can tell I'm using the thinnest head gasket available.

Currently redoing the floor under the seat, moving the seat back an inch and making new harness mounting points.

 

[smallfoot]

Keep picking at it Bob, you'll find it...

 

[old28]

Bob, I'm with you, no big motor changes at this point. A few small changes for a bit more power would be nice. Some weight reduction will always help. If you want to try the 1.75 aluminum race roller rockers I have a good used set with 7/16x7/16 screw in studs Ican send you, no cost, I will never use them. Hope the pictures come out. Tom

 

[kenny c]

The problem with making more than one change at a time is you don't know which one helped and what one hindered. I feel one drive train change at a time. Maybe one or two chassis changes. Moving the battery forward and the seat back shouldn't hurt anything. Will the rocker arm swap give give you a little more duration along with the added lift? You should get more cylinder fill either way I would think. Good luck. [P

 

[old28]

Yes on both lift & Duration.

 

[bob w]

Thanks for your generous offer, Tom. I'm going to see how it runs with the changes that are under way. If I need more, I'll contact you.

Been making small but time consuming changes. Cleaning up the floor, new seat belt mounts, moved the master cylinder and pedal forward. Making more cockpit room for Driver Dave. He bigger than me. One motor mount was cracked and bent. Will make a stronger one tomorrow. Too much torque.

 

[old28]

Bob W, sounds like a winner. Those 300 motors do put out some torque.

I would try it like it is too, studs & lifter are available
if you need them, just PM me.

How much weight would you say that you have removed from the dragster?

Dave should be a bit more comfortable in the seat this season.[cl

 

[bob w]

Made a stronger motor mount.

Three pipes down on the header. Three to go. If I did this regularly, a much better header would result. Pipes are 34" long. Collectors will be 18".

At least 100 pounds will be removed. If Dave gets liposuction that will be another hun.

 

[old28]

Bob W - Headers are looking real sharp. I would take all the weight off the motor/trans/ front & rearend/ frame that I could, Weight reduction from "Dave" might be a bit harder.

 

[Old Iron]

Bob, I know you're already rolling but have you considered running the tubes into each collector in their respective firing orders?
If this is correct for the engine you're using, 1-5-3 into one collector and 6-2-4 into the other. It would be like a set of 180 headers on a V8.