Mk IV conversion 302 small block to big block 427

[AC Ventura]

As of 2.30 this morning, after 7 months of intensive preparation finally, the big 7 litre 427 engine is able to check out its new home.
Thanks to Barry Rabotnic who built the epic motor and all my friends in the FB and other AC Cobra online communities.
Still a lot of work be done, but looks like I won't be needing a Tesla just yet.

[westcott]

Great progress, my former FE was also based on a Southern Automotive (Barry Rabotnik) short block. He supported the engine rebuild in my garage with his experiance and part recommendations.

It was a torque monster at the end.... 8)

You will like driving that thing around !

[AC Ventura]

Thanks Wescott !

Now the 5 speed TKO is in and I'm now working on constructing the engine mounts. I've tried very hard to keep the spirit of the Mk IV, meaning I've kept the glassfibre footwells, despite them being 3" wider. That alone took 2 months. I'm also keeping the under car exhaust, albeit a new larger diameter system.

.......and yes the bonnet does shut !

[mjf]

How is the big block conversion going - is it running yet ?

[AC Ventura]

I have stopped posting updates to this build, as judging by the lack of feedback/comments there is no particular interest in it. However, if you join the closed AC Cobra group on Facebook, you will see almost weekly updates with extensive pix and a very enthusiastic audience. Just search Mk IV 302 to 427.
  Currently fitting new hydraulics, then clutch fork indexing, custom built headers, all new exhaust system and finally all new electrics. Feels like we are breaking new ground with this build as it is intended to be a development of the 11 x 427 Mk IV's Autokraft made and not another Shelby clone. The work detail is vast as we are trying to accommodate the new larger drivetrain, but not lose the Mk IVs identity.  Feels like we are on the home straight now and I could not be happier how it's going. I expect on the road in Feb 2019....and simply can't wait. Confidently expect it to be as absurd as it will be fabulous.

[AC Ventura]

Looks similar to the original engine bay, but everything, steering, pedals, firewall has been remade to accommodate the big block. Everybody remarks on the striking, all new polished stainless firewall, but that was comparatively easy to make compared to everything else. Unlike other conversions, there's plenty of room for air to escape and crucially it's 3" wider than a few months ago. If anybody one day wants to put the original 302 back, there'll be a lot of room to work on it!

[AC Ventura]

......anti rip-out engine mounts, designed just for this conversion.

[AC Ventura]

In cockpit hydraulics, new pedal box and new one piece transmission tunnel with removable scuttle braces (not shown). Clutch can be changed in car and transmission can be removed without taking engine out. In fact I can remove engine, transmission bellhousing, entirely on my own in just one hour, albeit with the headers and ancillaries already disconnected.

[AC Ventura]

All new design pedal box, pre plumbed to make servicing easier in the limited space.

[mjf]

Thats a very big task you have taken on there, but you will know the car very well once you have finished.

I am sure spring and hopefully some good weather will arrive at the same time that it is finished.

[westcott]

That's good progress and well done.

Just turn the left pedal plate 180° .... ;)

Will You go with  single tube headers and slip in connections?

You will reach your timing target and enjoy your work in spring !!

[AC Ventura]

Damn...my pedals are upside down?

The headers are the next big hurdle. I'm not sure on the connection.....but a flange seems simpler to me. I'm hoping for a 2.5-3" under car system. I'm looking at Spintech mufflers.

[westcott]

I had single tubes but used side pipes on my FE powered Crendon. The slip in connection was easier and I never had any manifold to head gasket leakage.

Flanges were 10mm thick stainless and laser cut.

Single tubes make the installation and later service in the engine bay easier.


I requested some details for shipping costs and shipping in general from Spintech different times but they never replied.

My intention was to go with Sportsman 3000F low profile mufflers for the 331 in my MK IV but no answer till today.