Would converting to weber carbs hurt the value of my Sprint or add to the value or just be a wash ?
The head I would use is an early half moon head. It does have big valves.
Thanks for your input.
generally it adds value, especially to the resto-mod crowd. The purists might snicker who want originality. speaking of value, you’ll be spending a lot more investing into the conversion and may not get that investment back out of it. as with any restoration, you do it because you want it or love it that way.
IMHO skip the webers and go straight to Fuel injection… if you are not bothered about originality Fuel Injection just works way better in almost every respect.
I’m not sure how well the early head would fit the picture, not only because it would not match the period of the Sprint, but also because even with big valves they would flow less than proper Sprint heads…
If the rationale is to gain performance, I would precisely factor in all costs vs. the target performance figure (and the required amount of porting to achieve that), also considering a rebuildable used head of the later style or even a new head. It is very possible you’d end up with less performance with the stock old weber head even fitted with big valves vs. the original Stromberg if all is in good nick…
I have precisely that & I think it’s about awash.
Originality nuts prefer the car as it left the facxtory, but as discussed in another thread at the moment the Federal emissions stuff took 16hp away.
But if you swap headers for the cast iron manifold, remove the crosssover pipes & secondary throttle plates, recurve the distributor and change the carb needles, can’t you get that 16 hp back for much less expense/trouble than going to webers? (I hope so, because that’s what I did - and if “feels” like I got a good chunk of those ponies back).
But if you swap headers for the cast iron manifold, remove the crosssover pipes & secondary throttle plates, recurve the distributor and change the carb needles, can’t you get that 16 hp back for much less expense/trouble than going to webers? (I hope so, because that’s what I did - and if “feels” like I got a good chunk of those ponies back).
You?d be missing the higher compression (due to the head), but I think you?d be close…
Thanks everyone for the input.
If my compression was 10.3:1, how much lower will it be using the early head.

Thanks everyone for the input.
If my compression was 10.3:1, how much lower will it be using the early head.
The 4.60 inch thick high compression sprint heads had a nominal 10.3:1 comp ratio. The 4.64 inch thick earlier heads had a nominal 9.8:1 comp ratio. However most heads have been skimmed and otherwise changed over the years ( e.g. larger valves and changed combustion chamber shapes) and also blocks skimmed and pistons changed so you really need to measure and check as you cant rely on the standard numbers unless everything is to original dimensions and unmodified.
cheers
Rohan
The webers look cool and have a nice roar at WFO. Depending on the cams, cam timing, etc. they can be a challenge to get jetting and emulsion tubes right for drive-ability. Keith Frank’s kits of bits are a huge improvement.
On the other hand, consider some tuning with the Strombergs. I have driven several well tuned twincams on Strombergs that were more than the equal of a twink with webers.
YMMV.
Anyone who thinks that a Federal Twin Cam with all its attendant gubbins is only 16bhp down on an uninhibited UK spec Sprint engine is dreaming.
However, Lotus themselves got Stromberg-carbed engines to produce decent 115bhp-ish output without going nuts and my own Europa TC with D-type cams, header, new distributor, high-level intake adapters and all gubbins gone goes a lot better than it did, so good luck to you!
Emissions-stuff aside, I think the Strombergs itself is a bit unfairly maligned.
Emissions-stuff aside, I think the Strombergs itself is a bit unfairly maligned.
Do we have any idea how much the Webers (or DellOrtos) are worth over a same spec tc on Strombergs?
On the face of it they look like simple things compared to the twidlers paradise that are Webers but the subtlety in the design is often overlooked.
I am no expert but I’d expect the two to be closely matched until you got in to higher bhp engines.
The Weber’s can flow more air and probably more fuel so better for high bhp engines. Strombergs are probably easily to tune thou, do more likely to more optimally tuned that Weber’s.
I have a new TwinCam Webers equipped with MSD Distributor + MSD 6AL. Plenty of power.
Depending on Webers perform, startup drive-ability etc. I may further update to injection, DTAFast S40 Pro ECU and w/Jenevy classic 45mm DCOE throttle bodies, looks like webers but it’s injected.
I still have the original number matching Stromberg BV TwinCam but 113hp just didn’t wasn’t enough, just wanted to keep it original just in case.
Emissions-stuff aside, I think the Strombergs itself is a bit unfairly maligned.
Plus 1 to that and I no longer have a Stromberg equipped Elan.
I find a well tuned (European tune) standard Stromberg Elan a nice road car with similar top end power to the Sprint but more low down tractability, so in someways a nicer road car. It does not have the instantaneous “punch” you get when flooring the throttle in a Elan at around 3500 rpm however. Hot starting and run on after switching off is also sometimes a challenge with Strombergs with no easy specific fixes other than make sure everything is perfect and maybe the issues go away.
They can be developed to get around 140 to 150 hp with the right cams and a bit of porting but you are ultimately limited by the less efficient breathing of the siamesed inlets.
cheers
Rohan
All that said, who has ever opened an elan bonnet and gone weak at the knee’s saying
‘core look a set of stromberg carbs’ ???
I am in exactly the position of an Elan resto thats fitted with Strombergs
It will be getting a replacement head and carbs!
BTW, Rohan
My “new” Twincam uses a McCoy Stromberg weber conversion head.
(noticed your older posts).
Actually it’s a McCoy built tall block, 1950cc, 193 hp 7000, 161 lb-ft 5600
10.5 pump gas CR
Tim
As Rohan says, the head is the problem that limits Strombergs.
Having said which, I don’t suppose many people have bolted 4 Strombergs to an 8-port head!