Big Block vs Small Block

........... 8 years later.......
I'm a FNG to the forum, but have been following the GT40 for decades. I'm updating my research with the plan of starting my RCR GT40 MkII by the end of 2020.

This is a GT40 MkII specific question, as the SB/BB performance issue has been beaten on hard in this thread.

I can build a Ford 427ci, 500ish HP/ftlbs engine in either a newer technology aluminum SB, or a FE iron block side-oiler. Price, weight, size, and technology of the SB puts a lot of check marks in the plus column. However, the FE block has a big check mark in the authenticity column. The question is how big is the authenticity check mark?

Would the extra money required to acquire and build an FE side-oiler be reflected in the value of the car? In other words, would the investment be recouped in the resale? The resale market on these cars is all over the place after the "Movie," so it's difficult to judge.
 
And what transaxle are you going to choose, pray tell,???
And why go iron block FE when you can get an alloy FE block & heads that will weigh about the same as an iron SBF combo and make lots more Torque to break the T/A with or be like Kirby Schrader and drop an ex Nascar engine in it, they come with ~900hp on a 4bbl or you could restrict it a bit with those weber must have thingy's... you will be going that quick nobody will have time to see whats actually at home back there anyway. As to what it costs versus what it will be worth, to each his own!
 
Transaxle is another discussion......I know it's more important than the engine.....I get it.

This is not about my wiener being bigger than yours. I want a period correct power plant for the MK2. I'm open to a SB instead of a BB 427, especially if the BB does not add value.

I like the idea of an aluminum FE block, if it is a side-oiler. I feel that this is a requirement for an FE block that will be used in a high performance car. So, I guess that will be the first question I ask an engine builder.

Ford Performance used to make an aluminum small blocked 427 crate engine, but they are now only offering iron block......I wonder why?
 
Period correct for a MK2 would seem to dictate a FE of some description preferably with one or two 4bbl's, .... next question? Why does everyone need a 427-or larger, plenty of other capacity options out there particularly with smaller bores that are less prone to problems later on from coe shift, corrosion etc, after all not to many folk can tell one FE from another, you can build oiling systems that are more efficient than the side oiler these days if your a bit clever. ;) Alloy blocks need more maintenance, move around more and probably a warranty nightmare for FP.
 

Chris Kouba

Supporter
I want a period correct power plant for the MK2.

Looks like you just answered your own question then.

I'm open to a SB instead of a BB 427, especially if the BB does not add value.

Whoops, maybe not. If you're building it for you, build the car you want. Period. You won't need to worry about resale.

If you're building it for sale, think ahead to read the mind of your customer. Best of luck.
 
Good advice, all. I appreciate the well informed viewpoints of this forum, and I'm happy to be a new member.

Since there are fewer MkII's out there, and they were originally built with the FE 427, I was worried that there exists a stigma associated with engine selection other than the FE. Apparently not. More research to do!
 

Larry L.

Lifetime Supporter
I want a period correct power plant for the MK2.

Then the FE is the only way to go. To purests, small blocks look like fish out of water in a MKII.

(Plus, a dual 4bbl-equipped FE just flat-out looks and sounds so darned impressive!)
(Just make sure you research and note the location of all available gas stations along whatever 'extended route' you may wish to travel. ;))

JMPO OMV
 
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Howard Jones

Supporter
A 390 bore 30 over will get you 395 CI. and with good heads and 10 to 1 CR that should make right at 450HP and that is just about 1.13 HP per CI. That is a very mild pump gas motor and should live the life of the car. I would build it with hyd roller lifters and limit revs to 5800-6K. Alum heads and intake will save you a lot of weight and with proper selection be good for the target HP. IMHO the iron block is a better choice for a number of reasons not the least of which being cost. The iron / alum block weight difference is quite a bit less than a 100 pounds anyway. That extra weight is low and centered in the chassis so at least its in the right place.

Now Gearbox. Have one of the Porsche gearbox builder find you a suitable 930 4 speed gearbox and build it with a Quaife TBD in it. They are very strong and once correctly build it should be able to handle 450HP for the life of the car as well. I would not advise finding a gearbox for yourself and then taking it to a gearbox shop unless you have the skills to take it apart yourself and evaluate its health prior to purchase.

Most of the reputable Porsche gearbox builder would rather source the core for you anyway.

I agree that a FE would look more correct in a MK2 and a 4 speed Porsche 930 is as close to the T44 4 speed as can be had without speeding God only knows how much money for one.

So that's what I think and the advice is free.
 

Dwight

RCR GT 40 Gulf Livery 347 Eight Stack injection
I have a 390 in my '66 Fairlane dressed to look like a 427 ( with fake cross bolts). I bought the car like this last spring. For the last four months I have looked for a FE block that will bore to 4.23". I have gone though six blocks which will not bore to 4.23".
I may have located one out of state. Waiting to hear if it will pass a sonic and mag test. I know of one other 427 motor but he will not sell.
So from my experience I would say locating a 427 block is hard to do.
There are a few aluminum 427 block for sale.
"A MK II with anything but a FE motor has to be wrong."
But this is coming from a guy that wants a FE with a 4.23' bore and I don't care if the block came out of a dump truck or an RV. I can fake the cross bolt if it has the correct bore.
Each to their own.

And I think the FE in the MK II will bring more money and sell quicker in the world market.

My MK I has a 347 small block making close to 500 hp. I hope
IMG_0663.JPG
 
Fran Hall tells me that installing the FE engine in the RCR40 makes it very difficult to install accessories like air conditioning. You have to build a firewall bump, to get clearance to fit. I've also priced an FE build and it will be more than $10k what a small block build will be with the same performance. Essentially, I can have two small blocks for the price of a big block.
 

Chris Kouba

Supporter
Essentially, I can have two small blocks for the price of a big block.

Yeah but... What do you want?

This car is not about practicality or economy, it's about passion. They are built to be enjoyed, whether that means looking at, polishing, working on, driving, or a mix of all the above. It can be an era-correct reproduction or general tribute, a copy of an exact car, or somewhere in between those. Build the car you want- if you have the budget. If you don't, figure out the compromise(s) you're willing to make or what you're willing to do to fund the delta to make the dream car happen.

If the hassle and $'s of the big block aren't worth it to you, by all means, skip it. Equivalent performance can be achieved through other means. If a proper lump means something to you, go for it. No one on this forum will fault you for it.
 
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