Forward or rearward engine location?
 

Hello all, it's my first post! I've been doing a lot of research on the V8 swap and am set on getting it done, the boss gave permission as well so that helps! I have an '04 MSM that I'm currently selling performance parts off of and will be taking to a students shop to strip down and sell off other aftermarket goodies as well as the motor/tranny/diff/etc to help fund the project.

Thus far, the plan is to pick up an '06 GTO pullout as they're pretty affordable, I've seen them anywhere from about $5K-$6.5K, and they got rid of the throttle actuator control that year by incorporating it into the ecu. It's ridiculous to see how well the LSX motors respond to modifications, I've been researching cams and headwork, one company offers a stage 1 cam that doesn't affect idle and increase horsepower to almost 500, crank of course!

My question for all of you that have done the swaps are, which engine mount location do you prefer? The current plan is to use the Boss Frog forward mount kit along with their transmission mount and use Flyin' Miata/V8 Roadsters drive line kit with getrag differntial. Seemed to me to be the most cost efficient and effective way to get the car going. If I'm going to spend all of this money, I want to make sure it's getting done correctly the first time. Those of you that have used the forward mount, in either kit, do you wish you went with a rearward mount or are you happy with your choice? I'm sure the rear mount people are all happy with their choice, besides working on the transmission tunnel, I'm trying to justify the ease of install for the frount mount!

This car is mainly for my enjoyment, I've never autocrossed or roadraced and really don't plan on doing that, I just have to have a V8 Miata! Any and all help is much appreciated!

I've built 3 Ford builds which are only avaiable as a "front mount" solution. Even with the iron heads of a Ford 306 I've been very happy with the balance of the cars when done.

Another thought you may want to consider is the indication by some that the cutting and rewelding required for the reward mount may casue some distortion in the chassis. Some folks have been having trouble with thier doors not lining up properly after doing the cut-and-weld procedure.

Ultimatly it's up to you. I personally don't think the extra inch or so is worth the effort or risk. I am, however, a Ford guy.

-Jason

Also, you may be able to get the cost down even further if you use a Monster Miata Ford 7.5 inch rear mount. I think the whole thing goes for around $1000 including mount, axles and hubs and the differentials themselves can be found in yards with limited slip for under $100.

Thanks for the information! I am definitely leaning towards the forward mount kit, just waiting for owners of these two kits to chime in and give me their thoughts. I almost pulled the plug and bought one today but figured I should wait a bit to hear thoughts.

I'm curious to know if anybody else with the Bossfrog kit has had any fitment issues?

My wife wants an NA Miata and I'd like to do a Ford swap in one just to have both. We'll see how this project goes but I'm sure I'll be speaking with you about it later! Thanks for the help!

OT: Have you considered selling your MSM and buying another NB chassis for the swap? It's a shame to see one less factory turbo miata out there. Sorry for the off topic question.

I have actually, but the hassle of doing that and getting the same, or possibly even less, money out of the car isn't worth it. I understand what you mean though, I thought I'd be happy with all of the mods I've done and getting tuned but I want more! Who doesn't, right?

I've also thought about trying to trade it to somebody else with an NB plus have them give me cash. It's still got a little bit of time before it gets stripped, I just might try that!

Trading sounds like a good idea. I would think there would be decent interest in that. Here's the forums I know of:

www.miata.net
www.roadsterdrift.net
www.miataturbo.net
www.specmiata.com
www.clubroadster.net
www.mx-5.com

I am curious on the forward vs. rearward mounting positions also.

There's really no good reason to go with the forward mount setup. You lose important space up front for the sway bar, radiator and fans. Your shifter ends up a bit too far forward as well.

The rear mount is a little bit more work on the transmission tunnel, but I suspect the labor savings will be negated when you have to cope with that tight clearance up front. As for chassis distortion while making the modification, it's not that dramatic a piece of work. We've never seen any sign of distortion while doing it and you're not touching much of the structure of the car - the frame rails are still in place and providing much of the rigidity.

I say convert the MSM. We've done one already :) It's a nice platform, don't waste it.

I have the first V8 conversion that FM did after their test car, Elvis was finished. I'm happy to report that after several thousand miles of having lots of high RPM fun in it, that the doors still close with ease, the A/C still blows ice cold and everything still lines up nicely. This is a wonderful, almost maintenance free, light em up at will, car that you can actually use as a daily driver. We were very fortunate to hook up with Bill at FM early on. All the folks at FM are very knowledgeable, true professionals and they really do a very clean, "factory" looking conversion. It costs a little bit more to have them do it, but it's a bargain at twice the rate they charge. No regrets with this conversion here in northwest Louisiana. Were starting to look for an NC so they can do an LS9 conversion in the near future. 480 HP is almost enough but I think that 638 HP will probably be "just enough". If your on the fence about one of these conversions, know that this is one of those things in life that you will never regret! (the first time you run it thru the gears after the conversion, you'll wonder why you waited so long to do it) Enjoying every minute of my mid life crisis, Waterwellwizard.
PS: go with the rearward engine mounting platform, you'll appreciate the extra room at the front (because it is a little crowded) as well as great handling, just my 2 cents.

When I started the LS2 swapin my NA I ordered the Boss Frog front crossmember but as the car was going together I realized that the change in steering geometry would likely lead to handling problems later. After a long tussle with Joranlein at Boss frog I managed to get my money back and purchased the V8 Roadsters front cross member. Much better fit, much better design and it maintains the original steering geometry. The engine, trans, Ford 8.8 diff and axles are now in so the car should see the street in 3 mos. or so.

The construction of the Boss Frog stuff is several notches below the V8 roadsters parts and if i had to do this again I would not have used anything from Boss Frog.

I also used the V8R stuff (rear mount) and it's very good. The product support is also excellent as is the fit and finish. You can buy it direct from V8 roadsters or from Flyin' Miata the price is the same and both are great to work with!
Tom