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Hi Lads . I'm new here and hence my first post. My question is more of a general one than car specific. I intend doing a multiport EFI on my 68 Daimler 250 V8 using the existing Daimler manifold with injector bungs welded in on each leg fed by two fuel rails. I know already know that the alloy can take welding. I will dump the SU carbs and fit two Jenvey throttle bodies in their place with custom made linkage. More than likely a Canems ECU will be installed using semi sequential injection. I do not intend doing a forced induction system or expect any huge HP or torque gains but if I use a slightly hotter cam added to the EFI what sort of real world HP and torque could I expect to gain. My main priority is that she runs very smooth still as I use her for weddings ,coupled with low end torque increase and better fuel economy. The Daimler  when new had about 140HP  with not staggering torque. From your real world experience of similar conversions am I likely to make the gains I hope to achieve. My rear diff is going to be changed this summer with either the MK2 Jaguar 3.54:1 or the 3.77:1 ratio R/P.  With the standard carb set up I have been advised to go with the 3.77:2 diff but would the mods described above allow me to opt for the taller diff due to low end torque increases. Thanks in advance. Regards Kieran 




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Hi Kieran and welcome,

Dont know much about the Daimler V8 except that it’s a good strong engine with a hemi head, capable of good power, especially with forced induction. 

I’m not a big fan of using carb manifolds for injection, but I realise that creating one for FI is a lot of work even using parts of the original as a basis. Also the Daimler one looks better than some. You should still get the benefits of better controlled and more even fuel distribution between cylinders even if the basic flow characteristics are unchanged.

Yes, I would expect you to be able to pick up a bit of power and torque, but especially improve the spread of torque, especially if you use the ECU to control the spark timing, which you really should as there are big gains to be had in part throttle torque.

Cam-wise, if your goal is principally a smooth, strong low end, be careful with your cam selection and don’t go too far from the original timing. A bit more lift may be beneficial though. Not sure what is out there for them?

Don’t really know what to say about diff ratio, personally I like tall gearing, especially in cars I’m going to do distance work in. They seem to have been really short geared from the factory. I’m inclined to say the 3.54 and seems that this guy agrees


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Hi Nick.

Thank you for your reply.  I have read Robert Grinters report on diff choice but since posting I contacted the Guru of all things Daimler 250 Russ Carpenter who had the British record speed  in his drag racer in the 80s using the Daimler V8 getting 1500hp on Nitrous. His advice which I will take is to go for the 3.77 diff with standard cam and similar to your opinion he says I will make enough extra torque to counteract going for the taller diff.                                The Canems ECU will control the spark and with their latest V8 ECU fully sequential is available giving more control and fuel efficiency. Its an expensive ECU but worth the extra money to try to do it right first time. I am also on the look out for a J type laycock Overdrive which will be converted by OD spares in Rugby to a stand alone unit lowering cruising speed revs. The drive shift will be cut and the O/D bolts directly on to the gearbox.                                                My everyday driver is a 74 mk2 Stag which if the project with the Daimler is successful will hopefully ,when funds allow , get similar treatment . I would use a taller ratio diff from the BMW rear end . I did suffer the reasonably common fault of the stag diff nose cracking on me a few years ago. So anyone out there in Triumph land with a J type OD going for a reasonable price ease let me know. Thanks again Nick





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Meant to ask whether manual or auto..... Had sort of assumed auto as so many of them are.

Overdrive lets you have your cake and eat it to an extent, so with that in the mix, 3.77 would be my choice also.

J-type ODs are still relatively available.  So some variations in spec (not sure what they all are), but in many cases it’s mostly just different operating pressures which can be changed. Don’t forget they were used on Volvos in quite large numbers. Certainly on the 240 series and maybe even on the earlier 740s. Advantage of these is the are all 28% OD. One of our contributors (though he’s not been on for a while) found a new one and managed to fit it to his GT6.

Stag engine responds very well to FI. Had the pleasure of meeting Neil Brown (aka the Flying Farmer) at Castle Coombe last week as he was there with his EFI’d TV8 TR5. With 200+ bhp I didn’t bother chasing him on the track!  

Another contributor on here Steve, (aka Chippy) has made/is making EFI manifolds for the Stag engine and they look superb. Understand Neil is having one of those.


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