Author Topic: AC Mk IV 302 to 427 FE downgrade ......  (Read 661 times)

AC Ventura

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AC Mk IV 302 to 427 FE downgrade ......
« on: April 22, 2019, 11:19:18 »
Finally, the all stainless headers, 24" mufflers and undercar exhaust system are complete. Thanks to meticulous planning, the original ground clearance has been maintained and there is ample room between the header and the footbox for air flow and heat shielding, despite 1 7/8" primaries, 2 1/2" system. In a RHD car, the motor offset reduces the drivers footwell width by a full 1", compared to LHD, so you need to get your comprises right. Simpson Race Exhausts, here in the UK made light work of the installation and I particularly like the elegant and compact, one bolt jointing system used. Thanks to this the headers can be removed in situ, without removing the steering. Hopefully first fire up, the weekend after this.
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mjf

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Re: AC Mk IV 302 to 427 FE downgrade ......
« Reply #1 on: April 26, 2019, 09:05:43 »
That looks like a very neat installation. I hope the first start up goes OK and that you will be able to start driving it soon.

Are you having to upgrade the differential and what ratio are you going to use ??

AC Ventura

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Re: AC Mk IV 302 to 427 FE downgrade ......
« Reply #2 on: April 26, 2019, 18:20:24 »
It’s a Salisbury 3.54 with LSD, but by all accounts will need to be changed to 3.31. But as it’s already in place, might as well make up my own mind. Hopefully start up tmrw!
« Last Edit: April 26, 2019, 21:01:00 by AC Ventura »

mjf

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Re: AC Mk IV 302 to 427 FE downgrade ......
« Reply #3 on: April 29, 2019, 15:23:10 »
How did the start up go - are you up and running ??

1985 CCX

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Re: AC Mk IV 302 to 427 FE downgrade ......
« Reply #4 on: January 02, 2020, 17:53:43 »
Now that you have made this change would you:

a) Say it was worth it to go FE?
b) If you have to do over would you pick a small block Nascar type motor as it gives the power and bolt up to stock position?

BTW I love the FE change...
Jeff Gagnon
AC MKIV #1085 and CSX2375r

AC Ventura

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Re: AC Mk IV 302 to 427 FE downgrade ......
« Reply #5 on: January 12, 2020, 00:41:53 »


a) Say it was worth it to go FE?

 110%, but only with an aluminium block. It handles like with the 302, but has 2 1/2 times the output.

b) If you have to do over would you pick a small block Nascar type motor as it gives the power and bolt up to stock position?

No. I would only do that of there was no possibility of being able to do the full conversion. I mean the engine bay, footwells, interior, column, pedals, etc. This work is extensive, if you want to keep it looking stock.
 I originally was going to go 331 or 347, but felt I was selling out. I finally came  to rest with the FE and was very happy with that plan.  The Mk IV already has the 427, chassis, the 427 body and I wanted to experience the legend. Also all everyone asks apart from is it real, is is it really a 7 litre? It makes their day when I reply,  actually yes.

1985 CCX

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Re: AC Mk IV 302 to 427 FE downgrade ......
« Reply #6 on: January 13, 2020, 14:09:37 »
Awesome!
Car looks great, hope you enjoy it.
Jeff Gagnon
AC MKIV #1085 and CSX2375r