cheers for the kind words Sid, we had a lot of fun with the slingshot. We ran the V6 for 1 season and to be honest they're pretty limited in terms of development. We eventually hoiked it out and stuck a Rover in there.
And you're right mate, there is no known cure....on our fifth season and best to date is an 8.49 at 152mph, all I wanted was a little slingshot !.
To the young lad building the slinghot. Do yourself a favour and get hold of the SFI plans. Theres no big secret about how to build a chassis that will tag. It's just tube thickness and tube placement. The skill comes with building a balanced chassis, well proportioned and most importantly safe. Not being funny but there is some ugly cars out there that have tagged as they are safe, just ugly.....so use the right materials and construction. No need to CAD this or that, the plans are already there, why re-invent the wheel ?
Big things for your build, use the correct grade CDS steel, have the bends done for you on a draw round mandrel bender. Make sure the chassis is built on a jig, properly square and unable to move whilst welding. MIG is fine for steel, tig for moly. Pay attention to the seating position, you still need to be able to drive the car. Mount the rear axle in double shear, use the correct grade bolts on the rearend, and use an anti rotation device. Make sure theres ample cage clearance to your head when seated, suited, belted and with a helmet on. Make sure you have the proper front end geometry, to avoid bump steer and ensure it's stable at speed. Above all buy the plans, it's too much work and cost to go your own route only to build a car that has no future other than RWYB or that isn't safe.
On the motor the v6 is limited. If you build your car around an under powered lump now, it'll be more work later when you work it out for yourself. I ran 13.01 with an Essex and manual box, fun for one season then went to a Rover. Pick up a cheap cut out Chevy with a glide or th350, much more scaleable in terms of development. A Rover will get you down into the 12's, poss 11's, but they're weak and £££ to tune. Go for an autobox. Manual is fun but you'll end up breaking diff's, clutches and shafts,plus an auto will be quicker and easier to shift ina tight cockpit. Four gearchanges in a 1/4 mile even lightening quick at .25 of a second is still 1 second. Auto box is half that.
Good luck with your build, feel free to ask any questions, and get yourself joined up to the Wild Bunch, lots of knowledgeable people and resource who can help you.