331 V8 Miata first autocross

Here's my first autocross after getting the V8 conversion complete. The on-board video recording had some problems, but I pieced together what I could. It was a good day. Only real mechanical issue had to do with the power steering fluid overheating. More video on vimeo[dot]com

Category:

Autos & Vehicles

Tags:

• V8
• Miata
• 302
• Ford
• 331

[xbfalcon351coupe]

just curious - how much stiffening do you generally need to do to the body shell etc on one of these? You see them fairly cheap these days, and obviously yours handles really nicely too - seems like a great base for a cheap(ish) performance car.. don't suppose you have a website or can recommend any good build sites?

[TopdownMX5]

@xbfalcon351coupe For stiffening, they are ok stock (i.e. you don't have to add much) but most folks tend to have firmer suspension components and a roll bar to make a more solid ride. My site is topdownmx5(dot)com but a couple other sites I'd recommend are: mccullyracingmotors(dot)com , swaptastic(dot)net/ls1_miata/ , and this forum: forum(dot)miata(dot)net/vb/for­umdisplay(dot)php?f=38 PS: change the (dt) to . for the links to work.

[xbfalcon351coupe]

@TopdownMX5 Cheers mate,I've never really considered one before - I mean, they're such a nice looking car but I never even considered that they'd be strong enough for a V8 with no real stiffening - wow... I'll check out those sites (thanks) hmmm, I think I might have lined up my next project...thanks again!

[TopdownMX5]

@xbfalcon351coupe Yep, the miata chassis takes a V8 quite nicely. Most common swaps are Ford 302's and Chevy LSx based. BTW, I only know of one 351 in a miata, but heard fitment w/ headers and hood clearance was a major pain. 302 (stroked to 331 or 347) fits better. Anyhow, enjoy reading up and researching. Good luck on your next project.

[xthexemoxmuffinx]

what region is this? SCCA ran autox? if so, greetings from the alabama region!

[TopdownMX5]

@xthexemoxmuffinx Central Kentucky Region SCCA.

[MrSweetleaf92]

I personally would rather do a rotary swap but this thing looks and sounds awsome! if i did a V8 Monster Miata i would want it just like this!

[supersoni126]

@TopdownMX5 really? wow because my uncles stock C5 gets almost 40 mph...of course hes literally always 5 mph under the speed limit but id expect more from such a lighter chassis..

[TopdownMX5]

@MrMayday7777 Not good. Only around 11-12mpg around town and 18 on the highway. If the engine were a stock 302 from a Mustang, w/ EFI, stock cam, etc... it would probably get closer to 16-18mpg around town and mid 20's on the highway. At least that's what others have said that had V8 miatas (based on their cars).