Power choices

[Callaghan]

I've recently placed an order for a SPF Mk2 GT40 and am trying to come to a decision on power. Looking at Shelby, Windsor, and Roush. I've heard some issues with aluminum blocks have risen recently but nothing first hand. I would very much appreciate some guidance from the learned crowd. I have a couple of months before the engine must be ordered. This car will see track days but will mostly pull road duty for living the dream and I am going with eight stack injector set up. The question is which block. Thank you in advance.

 

[Callaghan]

No one?

 

[Jac Mac]

Might be the way you asked the Q... As its a MKII do you want an FE or Windsor based 427, then who do you want recommendations as to the engine supplier/builder and then iron or aluminium block. Personally if your not going to be 'hands on' yourself and want something that will stay together for a long time and the track days are about having fun vs winning then go for an iron block at least, it simply wont move around as much as an alloy one and therefore wont require frequent spanner time to keep everything leak free. FWIW I would keep an FE at std bore and stroke rather than some of the big cube stuff everybody else seems to think they need.

 

[Randy V]

Might be the way you asked the Q... As its a MKII do you want an FE or Windsor based 427, then who do you want recommendations as to the engine supplier/builder and then iron or aluminium block. Personally if your not going to be 'hands on' yourself and want something that will stay together for a long time and the track days are about having fun vs winning then go for an iron block at least, it simply wont move around as much as an alloy one and therefore wont require frequent spanner time to keep everything leak free. FWIW I would keep an FE at std bore and stroke rather than some of the big cube stuff everybody else seems to think they need.

We need a LIKE button....
Spot on Jac...

 

[Mike Drew]

Amen brother!

The SPF Mk II is attempting to replicate the original, and is the only Mk II style car made (apart from some one-off ERA and Safir cars).

An iron block FE with either single or dual four-barrel Holley is the only way to go IMHO.

Although I freely admit to being strongly biased towards the Mk I with a small block and Webers.....

 

[Grady]

I've had two MkIIs. Both with FEs. One Iron (old NASCAR block) and the current engine is a Shelby aluminum. The Shelby is squared at 482 ci. The Shelby engine was developed using a 750 and 950 cfm Holley. Both were run on a dyno. Both were close as the 950 was correctly jetted for engine. The new 750 is in the box it came in. Results was 600/610 less gas and more air and it is a thing of 'great beauty.' Very smooth roll on from lower RPM that pulls well into triple digits on the speedo in 4th gear. The iron block was good but the cam wanted to be operated in the mid and higher RPMs. The limiting factor is cost. They Shelby engines are costly.

But a MkII needs a FE anything else does not fill out the engine bay.

 

[Mike]

Any trouble with keeping things sealed up with the alloy block?

 

[colin artus]

Iron block, Medium Riser aly heads (Shelby?) and hydraulic roller cam. The 427 block was definitely a step up from its lesser bretheren , I assume the modern copies adopt those advantages as well. Some mk11s ran 50ida webers so the 8 stack isn't an unprecedented look. A lot of engine displacement equals a lot of torque which will stress the trans unless you fit a t44 copy or something equally expensive.

 

[Steve]

Agree with Mike. No 427 Windsor. If you're going MkII, keep it true. FE block. Not sure that aluminum block adds much (or enough to justify the cost). If you want to keep it FIA legal for vintage racing, stick with iron block.

 

[Grady]

Any trouble with keeping things sealed up with the alloy block?

No Leaks anywhere. Only problem I had was a water pump interior failure.
The picture shows how well the rear compartment is filled out.

 

[Brian Kissel]

Grady, all that engine, and luggage boxes also. Looks fantastic. FE all the way.

 

[Andre]

Sorry to hi-jack the thread...I am in the market for a proper 427 sideoiler for my project....Anyone have any good suggestions for where to fine one ? I have looked for a while, but not been very succesful. I know of one very good source, but just interested to check if there are other sources availabl as well. I would also need the correct drysump registers, and sump....Brgds ! Andre

 

[Tim Terry]

Even though I went Roush 427SR for my GT40 build, I was going to chime in on the same subject as Andre: Availability. When I was building my Cobra, I went looking for a used iron FE. After realizing it was hard to determine the pedigree of some used blocks, not to mention the prices of original side oiler blocks, I decided to go with the Shelby 427 aluminum block. It was worth the extra money to buy new and know it was pristine.

My two cents.

 

[Mark]

I have a MK2 as well and since these were known as the big block cars, I went with a dual quad FE. It clearly fills out the engine, especially with extras like luggage boxes and a dry sump tank. Mine is a Shelby block and I have the typical rear main drip. That should be the biggest inconvenience in my life as a result of my build process.

 

[Callaghan]

Iron block, Medium Riser aly heads (Shelby?) and hydraulic roller cam. The 427 block was definitely a step up from its lesser bretheren , I assume the modern copies adopt those advantages as well. Some mk11s ran 50ida webers so the 8 stack isn't an unprecedented look. A lot of engine displacement equals a lot of torque which will stress the trans unless you fit a t44 copy or something equally expensive.

Thank you.

 

[Callaghan]

Thank you gentlemen I really appreciate your input. I know just enough to get myself in trouble with this subject. Looking at an approximate deliv date near Nov-Dec. This will be an absolute dream come true.