Advice opinions please

[David C]

My understanding is that the flap in the offside exhaust is totally unrelated to the type of choke you have. The choke on the carburettor provides richer fuel to get the engine started. The flap in the exhaust shuts down the offside pipe which means exhaust gasses from that side of the engine have to pass through the inlet manifold and exit via the nearside exhaust, warming the inlet system as they go. As the engine heats up the bimetallic strip opens the offside exhaust and both pipes come into play.

The flap valve should regularly be lubricated with graphite. The easiest way to do this is to use an aerosol of penetrating oil with graphite. A little tricky to find but I have found it on Ebay.

[DODD]

Are you referring to the Edelbrock carburettor or to the original Carter carburettor fitted to the 410 which had the bimetallic strip in the inlet manifold which indeed operated the choke to enrich the mixture?

The choke on the Edelbrock is electrically operated and does not require the gases to circulate around the inlet manifold to trigger the bimetallic strip. I think these V8’s generate enough heat in a very short time to turn off the electric choke on the Edelbrock.
Yes, prior to the Edelbrock installation the butterfly in the exhaust manifold would be closed and the choke on the carburettor would also be closed for ease of starting; as the gases pass through the inlet manifold they warm up the bimetallic strip and open the choke. Hopefully at the same time the heat control valve on the exhaust manifold opens fully.

I appreciate that warming up a cold engine gently but quickly is more beneficial to the life of the engine but once the engine to up to temperature I wouldn’t want a sticky heat control valve in the exhaust manifold or additional carbon build up behind the plate inside the inlet manifold giving me unnecessary heat issues. My motto is to keep it simple.

[David C]

Neither. The bi-metallic strip wound round the end of the butterfly spindle in the valve that shuts off the exhaust.

The type of carburettor really isn't relevant.

[David C]

I think you are referring to the bi metallic spring that sits in the inlet manifold and operates the choke on the Carter. This is indeed redundant if you go for the Edelbrock with electric choke or indeed a manual choke as was my choice.

The exhaust butterfly has no connection to this. It is a relatively subtle improvement during warm up so if you are anxious it may stick you are probably better to wire it open or remove it. However I never had any issues when using the car regularly. As long as the spindle is kept lubricated the weight is plenty to keep the valve open.

[David C]

A little more thought and I think I see where you are coming from. Sorry if I'm a bit slow. Yes, the exhaust gas going through the inlet manifold would warm up the original auto choke faster but I believe its main purpose is to warm up the whole inlet tract and this will have a similar effect regardless of carburettor type.

[AndrewA]

Whilst in limbo, have not been idle. With a lot of stuff out of the way gave engine bay and block a good clean and it came up quite well. Renewed all the bushes on front anti roll bar as they were tired and had a critical look at all the other bushes at the front end - which appear to be new or very recent. Fitted new shocks all round - GAZ adjustables - springs were new last year before I took possession. This was all stuff I'd identified and planned to do over the coming months/years and had already accumulated the bits.

[AndrewA]

Am back on the road - or I was briefly - but more of that later.
As per below have now been through front suspension in its entirety and then turned attention to the engine. Decided to renew anything suspect so new cam, followers, pushrods, water pump, timing chain and sprockets, valves, collets and had the heads done.
Inlet manifold looked decidedly mucky particularly under the metal plate on the underside so took the plate off and there was a big crack.
Had an extremely generous offer of a loan of a manifold from a contributor on here to get me rolling again - thanks again - but in the end SLJ were able to supply a second hand one at a reasonable cost. After a weekend of cleaning it to within an inch of its life it's now painted and on the car.
After "breaking in" cam, initial driving impressions are excellent - not a night and day improvement but engine even smoother and handling great - and that's before doing the geometry properly.
Only fly in the ointment was a petrol pong which I presumed would be something not done up properly in the engine bay. Not so - I had a boot full of petrol (again), culprit being the SU fuel pump. Have had enough and am going the Facet route - even if it means building a little sound proofed home for it in the boot.
It might be of use to some to know where I got the various bits and bobs from so here goes.
Timing chain and sprocket, full gasket set for poly engine, valve springs, harmonic balancer all came from Real Steel in Uxbridge.
Cam, lifters, valves and collets came from Falcon Global in the USA.
Pushrods from https://egge.com/
Bushes and other suspension bits from Classic Bristol Car Parts and SLJ (who also provided water pump).
Track rod ends - Amsteer.
Thanks again to those on here who have been in touch with advice and offers of practical help - much appreciated.
Andrew