Engine upgrades

[1977 interceptor]

Hi,

I am looking at buying and Interceptor to restore. I’ve seen some of the articles on the forum about the cost. I have a factory restored concours wining Jaguar and other restored classics so know the deal about the economics of this route.

Looking at the restoration blogs on the website, it looks as if the risk is that you buy an English car which looks superficial ok but is hiding a huge amount of rust which will have to be dealt with at some point. It seems to me that you either buy a car with a documented restoration or start from the ground up.

The other issue is that I would like to improve the fuel economy of the car.

Given all of this, I was wondering if it would make sense to buy a Californian shell with no engine and box and which is very structurally sound, convert to right hand drive (my restorer who is a well regarded 60s Ferrari specialists thinks this should not be too complicated given we would be replacing the wiring loom anyway) and update the engine and box with something like an LS3 plug and play package. The alternative would be to buy an original engine and rebuild with fuel injection and add a modern box. The LS3 package apparently returns 20- 22 mpg. Unsure what an injected 6.3 would return with a four speed modern box. Given modern traffic conditions any of these options would be powerful enough so more interested in maintaining the character of the car, fuel economy and drivability. The only other question is whether suspension upgrades are a must (obviously brakes would need to unrated) if you for for an LS3 given the extra torque and the effect that might have on the rear leaf springs.

The car is a mark 2 hence the 6.3 original engine. Presume if I go down this route better to stick with a 6.3 for cooling. Finally, presume a series 3 interior can be fitted to a series 2 car.

Thoughts very much appreciated.

[RockyUSA]

I would love to do all (or any of) the things you say, especially if you have an original car beside it!

I would encourage you to look at the threads by MarkI ("New Build From the States"). He has three Jensens, all done to the highest standards. I started this at the first picture of Mark's engine I could find, but there's more of his build at the beginning of Mark's Thread.

https://www.joc.org.uk/forum/viewtopic. ... s&start=22

I believe that he kept the original "type engines" (the 383s, IIRC) and has uprated them. They all look super, and run great.

I am not saying this is the way you must go - actually, I'd be more interested in a Gen 2, or Gen 3 Hemi in the car, to retain the Mopar Connection, but.... Honestly, a more modern drive package like a Hemi or LS3 would give you more room in the engine bay which would give you more cooling options, and make the layout easier.

I am glad you mentioned a new transmission, I would recommend you consider this. I have a GM 4L60e (4 Speed Electronic Controlled with Locking Overdrive) and rear end gear changes. I get the same final drive ratio as the original, but better acceleration due to the lower gears.

Anyway - keep us posted.

Rocky

PS> The money you save in gas will be a drop in the bucket compared to cost of a resto (as I am sure you know)... But it might be convenient to not have to fill up as often.

[BritArms]

Buy one thats already been done..Then fuel inject it

[Pymmie]

Hi 1977Interceptor,

Welcome to the JOC Forum.

I have one of 332RHD early Mk3s which came with the 383 from new.
Known as a G series & built between Aug71 - May72.
That would solve the interior upgrade!
As for EFI & 4 speed/overdrive it’s been done very successfully by a
member of this forum - Steve Payne. He returns low 20’s and knows
Jensens like the back of his hand.

Might be worth searching the forum for info.

Regards

John P

[Steve Payne]

Thanks John.

EFI and Overdrive is doable but a sound shell is going to be your challenge, yes converting a LHD car to RHD is possible and there have been cars converted in the past. One of the problems with Californian shells though often rust free they can be in poor condition through accident damage ether minor or major. One ex Californian car I have seen was obviously bodged up to sell and had a lot of filler to make it look good. Under the filler were numerous dents and dings.

What ever engine you decide to fit if it has a large capacity it will still use a lot of fuel, even the modern large capacity engines fitted to cars made today will only do the claimed MPG if driven like a Nun.

If I was to start again I would find the best car I could afford that somebody else has spent the money on and then do the upgrades.

Steve

[Richie]

Could you squeeze this in?

[Robinson D]

Probably rear-mounted, but you would want to take the afterburner off.

[RAP72]

Probably rear-mounted, but you would want to take the afterburner off.

depends who or what is behind you

[Joe Schiavone]

Steve has given you good advice. You know the costs involved. You are dealing with a 4200 lb car with a full tank and no people. Add two people add 400 lbs. we are now up to 460 lbs. go to you engine man and ask him to plug in all the necessary change to get your performance. The tranny and rear end ratio may get you the MPG’s but the performance may not snap your neck. Take Rocky’s advice and talk to a man who knows both ends of the equation RacerJoe

[Julian]

My 2c worth .... it all really depends on how you plan to use it.

Body-wise it can all be rebuilt, so too the interior- pretty much all the parts are available somewhere. Even starting with as good as a body as you can find it sounds like you will start from scratch anyway to get the quality you want. I bought a multi ex-concours winner ('90's) and it's still going strong.

Mechanically i wanted it to start, go and stop like a modern car. I injected (Edelbrock) my 440 in 2007. there are a few alternative systems now and all have or are probably being "justified" on the basis of easy starting, possible minor fuel savings, less maintenance ... all of which is true. Economy-wise sticking with the Torqueflite means mid teens is probably the best you'll see. but it is smooth and strong.

A different more modern auto is possible as you'll read and will certainly improve economy and performance - but that does matter enough to me to make a change. i already have enough speed in a straight line ... and the fuel in the scheme of things is negligible.
That said if there was a kit for a 6 speed auto i'd be interested (idle hands...)

With regard to performance I upgraded the brakes a couple of years later - and it now stops like a modern car. There are a couple of options around at least. Easy smart thing to do i think - albeit that you need the larger 17in rims (which gives you access to better tires)

That leaves handling. My suspension is standard albeit with adjustable shocks. It rides fine for what it is - a 60/70's GT.

A wholesale change in suspension is expensive and a lottery results-wise to some degree. you can tinker with angles at the front. a change at the rear impacts exhaust routing, spare wheel and fuel tank. for me its simply unnecessary. Standard is robust and effective enough for my needs.

If i were in the UK i'd try and compare a few cars. From stock to the latest JIA offer. What a great project for 2020 !

[1977 interceptor]

Julian,

Thanks. The LS3 idea was because one of the cars I have been offered has a very straight body but the engine has been removed. A new LS3 crate engine seems to be about the same price as buying an original engine and having this rebuilt.I am trying to work out how much work it would be to fit this in place of the original. If it’s a case of engine mounts etc that’s fine but not keen on re engineering the car.

It seems the consensus view is the key to improved drivability and economy is to upgrade the box and possibly add fuel injection and I think I might go this route. I’m not going to get into suspension upgrades but agree better brakes sensible.

[Julian]

Hi in that situation I'd go the LS3 route rather than source a 383/440.