Tried to answer your questions best I can.
Thanks for the replies folks. How reliable are the modern Shelby FE 427 engines? Do they have any known issues (leaks, etc)? Is a smaller engine punched out to 427 more reliable than a big block 427? Can a SMB punched out rev higher more reliably?
I don't really know how to answer this. These engines are mostly custom, even the Roush engines are not put through the same type of rigor that Chevy / Porsche / BMW do. In addition you may end up with leaks because of the installer which has nothing to do with the engine builder. If you want a high rev'ing 427 then you will need a fully custom motor from a builder that says they know how to do it (hopefully they actually do).
There is then a real possibility that the builder is more used to a race motor than one that is used for street duty which brings an entirely different set of characteristics. All that said, I think you will find more options for a high rev'ing engine from a Small Block Ford vs a 7L.
Everyone is different. I’m going to be very honest here that I dont like sudden burst of torque that lasts only 2-3 seconds and I am at redline and have to shift. Unless you are on a tall gear like the 3rd or 4th, you dont really get an experience that lasts very long. I owned a C7 ZR1 and basically with 755 hp/ 715 ft lbs of torque, car was utterly unenjoyable in first second gears. 2nd gear was done in no time. Only in 3rd or 4th you really felt the combustion engine going properly. I have a background in N/A cars with high redlines. I drive a 911 GT3 that redlines at 9000, had a GT350 8250 rpm and had an E90 M3 at 8500 rpm. I dont want to go fast, I want the experience and sensation of going fast in a race car.
I get the point of wanting a high rev-ing screamer, they are a riot. I have a GT3, have had an M3, used to race shifter karts, and now race a 10K+ RPM Radical, it is super fun to wind the cars out.
That said, high RPM doesn't always mean the best power delivery for every car, transmission, tire mix. In my GT3 I wring it out to 9K because that is the best power delivery. When I had the GT40 I actually found myself shifting at 5,800 a lot because the torque of the engine was so high at such a low RPM that I was getting the needed acceleration on the street. GT40s deliver power far different than a modern car, it took me a bit to get used to it and find enjoyment out of the experience.
That being said, I have been dreaming about #1 ken miles car for years and that car had a 427 7.0 liter in it. No mine wont be RHD, its a LHD so perhaps its not correct to state mine is period correct 100%.
Whats the highest reliable rpm I can expect out of a 427? Reliable means no solid lifters. No valve lash adjustment. Turn key and it goes. It sees a few redlines per 20 mile drive and is driven 4000-5000 miles/year.
I mean this in the nicest way possible. Have you been in a GT40 at full tilt yet? If not, I think it could be worth searching around the country for folks that may be willing to give you a ride. I can tell you that every GT40 I have been in, no matter what engine, is loud and raw... and hot. Candidly I would suggest you may not be able to feel the difference between any of these engines on the street, they will all feel like a hand of God is pushing you while your ear drums are screaming.
Re originality, I honestly think that going RHD is a bigger give away on "keeping the car original" than any engine. If you want LHD, all the power to you, mine was and it was great. But if the focus is being original then you will see the steering wheel no matter if the rear clam is up or down. A 427 will look just bigger in the back and create a lot more heat but I struggle to find the value prop is wanting a bigger and heavier lump in the back other than telling people it is a 427.
There are a few big block cars on this forum and they look great. If the look of that engine is what is doing it for you, all the power to you.
My GT3RS and GT350 and M3 all have been extremely reliable. 9000 rpm is something everyone must experience. My car is modified and makes close to 600 hp and weighs 3100 lbs. not as light as GT40 but still in today’s standards its light. My shelby has lasted almost 90,000 miles and didnt even have any hiccups. My M3 was good for 30,000 miles before I sold it. So higher rpm motors arent all a death sentence.
I don't think your requirements (low on maintenance, 427, and high rev-ing) can be delivered. The cars you are comparing to are modern engines, the 427 was not built to run high rev's and low maintenance. A GT40 is a long way away from a modern car in terms of nearly everything, including that it is going to need a lot of attention even if you don't go custom race engine.
I was told to go with Quaife transaxle. Would that handle the torque/power?
Re: Quaife; I think they are supposed to be good up to 550 although maybe that has changed (more?). In my experience, it is a fine transaxle and it worked for me well. There were comments a while back that spare parts were a challenge for a bit. A few years ago there was a dearth of any transaxles. Oltoff may be able to tell you about their experience with the Quaife in recent history.
That said, Quaife is not anywhere near original and the back looks different than the ZF (this is another transaxle option) which is different from the T44. Again, I don't think that really matters and it didn't matter to me when I had it, just pointing it out.
The above are just my opinions
Kevin
