V8 Miata, the Ultimate Hybrid Vehicle!

[moparguy]

Just sharing; being a old sports car guy from way way back I've always liked the little Mazda Miata. Problem is it's known as a girls car which is generally not a good thing. They drive great, are one of the very best engineered and made cars to every hit the road and most importantly, the top goes down. BUT, this is America and you can have a V8 and that dose of testosterone that's needed. The two common "man" engines used in upgrading T levels are Ford 5. 0s (302 to my generation) and the LS series GM engines.

The good news is total weight increase is less than 200 lbs and weight bias goes from a perfect 50/50 to a very very OK 49/51. My car weighs 2540 lbs with a 1/2 tank of fuel and me in it. Weight difference is about like having a passenger in a stock Miata.

My humble little car has a 90 mdl. Ford 5. 0 from a 90 Mustang GT, currently bored 60 (ultrasound test said it's good at 60 over) making it a 310, running the stock GT roller cam, AFR 165 aluminum heads, Edelbrock Performer intake, 625 cfm Edelbrock carb (knockoff of a Carter AFB) and modified 1 1/2 headers though 2 1/4" dual exhaust. Transmission is a Mustang T5 from the donor car and the rear is still Mazda Miata IRS looking, but sporting a 8. 8 center section (rear end) from a 1992 Thunderbird. Gears are 3. 08 posi. Axles are from Factory Five Racing, designed and manufactured for their excellent Cobra replica cars and luckily work in this application with a few mods to the rear swing arms and hubs.

I've just re-installed the engine after pulling it to do a mild wire tuck (remove unnecessary wires and hide the rest), painted and detailed the engine compartment, installed the new AFR heads and a new clutch along with a set of Scorpion roller rockers.

And yes, these little cars are as good as you might imagine, better likely. Pull like a jet leaving the runway (I truly think my pretty much stocker will run low 12's or better), gets in the low 20 mpg's on the road and once properly sorted out, just as dependable as a stock Mustang or Miata.

 

[HBarlow]

I'd love to take a ride in it with you. I'll guess it can push a passenger back against the seat very easily. I've always liked Miatas also.

 

[RustyJC]

My uncle's shop built the 1. 0 version of this, I guess. HiPo 289 and 4 speed swapped into an MGA back in the late 60s.



Yours is a very nice swap, however. Very clean.



Rusty

 

[S.Morris]

Very nice. My wife has a completely stock 91 Model. Its not quite as quick as yours though

 

[JR]

Im surprised how much room is in the engine compartment! What engine came in it from the factory? My friend used to own an RX7 that was a screamer. Ive always liked the Miata (and the Mustang). Had an 86 302 when I was a teenager that got me ina lot of trouble. The wife drives a newer model GT with the 4. 6 in the summer, when she gets a little less attached Im gonna pop her cherry and start squeezing some more ponies out of her . Its the sohc motor which is cheaper/easier to build. Thanks for sharing that, MoparGuy. Very neat conversion!

 

[Newt]

Now that looks like a fun car.

I had a Toyota Land FJ40 one time with a 327 Chevy. It would set you back in the seats. But, it had 4. 10's.

Newt

 

[BigPapa]

Stacy David did one on Gearz called the Banshee. Pretty cool.

http://staceydavid.com/projects/banshee

#ad

 

[rscurtis]

Many years ago, I saw a Triumph Spitfire that had been repowered with a big block Ford FE engine. The valve covers were even with the top of the fenders. Needless to say, it didn't look as good as yours does.

 

[Flying_gage]

MG,

Couple questions:

1. ) Did you perform the swap yourself or acquire it this way?
2. ) I assume mostly Monster Miata stuff in your build?
3. ) 3. 08's out back? Assuming you have the t-5 and the standard gears, is this enough to keep her being a little difficult to drive?

Like I mentioned, I a looking at the same swap down the road and really curious as to your experience. Will probably go with a LS series engine, (even though I have two notch back stangs) I really like the R&D that is currently being put into that motor.

Thanks

Pete

 

[RustyJC]

One of the new Ford 5. 0 Coyote engines would be sweet in a Miata if it isn't too wide.

Rusty

 

[moparguy]

MG,

Couple questions:

1. ) Did you perform the swap yourself or acquire it this way?

Bought on Ebay as a poorly executed home built. I've spent the past two years taking apart, improving, cutting out ALL the typical Miata rust and welding in new metal, painting and just generally taking my time to build a nice car.

2. ) I assume mostly Monster Miata stuff in your build?

The original builder duplicated the kit offered by the original Monster builder. I've just upped the level of craftsmanship.

3. ) 3. 08's out back? Assuming you have the t-5 and the standard gears, is this enough to keep her being a little difficult to drive?

The high gears work better than I expected. I live in a pretty rural setting with a lot of narrow paved roads and you don't use 5th much. However on the freeway at 70 the engine is only turning 1700 or so rpm (if memory serves, actually think it's more like 1650) in 5th. Due to the hp to weight ratio no problem off the line due to gears. Given the choice, I'd opt for 3. 27s, however not worth the effort to change.

Like I mentioned, I a looking at the same swap down the road and really curious as to your experience. Will probably go with a LS series engine, (even though I have two notch back stangs) I really like the R&D that is currently being put into that motor.

LS engines are what's happing, 400 plus hp stock, 27mpg regularly quoted by folks running L33's and LS1s. I recommend you check out miata.net. There's a engine conversion forum on the site that has several LS conversions by good folks that are super helpful. I also know of a couple for sale it you want info send a pm. No affiliation, just info.

Thanks

Pete

Hope that helps, RR