you can try rexhp.com there site did have both items on them

you can try rexhp.com they show intakes & timing covers on there site last time I looked 

Noted the comment about driving a cold engine with the choke full on for up to 10 minutes... in a word, not a good idea!..
P.S.- re read your posts & noted that U recently bought a Mummert aluminum intake.. Getting heat to the carb area or not is irrelavent, because unlike a "B" or Blue Thunder intake, the Mummert does not have a crossover...   


Paul

Doing away with the heat riser valve and having a dual exhaust system simply slows down the natural heating of the intake manifold.  In fact, if the exhaust system is unrestrictive (very little back pressure) then exhaust flow through the manifold will be very little and ineffective as far as actually preheating and adding heat to the intake plenum.  Without the heat riser valve, the intake manifold just warms up much slower and heats up only as a result of conduction from the cylinder heads.  If there is no exhaust flow through the manifold either as a result of blocked heat crossover passages or a very non-restrictive exhaust system, then carburetor icing when the temperature drops below the dew point becomes a real probability.  In the normal scheme of things, preheating the manifold via the heated crossover is only required until the intake manifold becomes the same temperature as the rest of the engine.  After that point, it’s no longer needed and in some instances becomes a detriment.

Lorena, Texas (South of Waco)

Thanks for the reply. I recently purchased an intake from mummert.  I am still looking for an aluminum  timing cover and a points style ignition distributor with 
vacuum and centrifical advance though. Thanks again Joe 

Located in Harford County Maryland 

have a bseries 4v 250 us, shipping would  be from blain wa. cliff ct1940@shaw.ca






2shaw.ca

Ted: Can you help and try to explain if/how or maybe the lack of a heat riser impacts the crossover system? For example, say a set of Rams Horn exhaust manifolds. I've never have had a real warm and fuzzy on exactly how it all worked in the OEM setup with the crossover exhaust.

In other words for simplicity's sake there were two (2) possible conditions, flapper open or closed in the original setup, now does the installation of dual exhaust manifolds without any heat riser result in some kind of weird condition that is neither good for hot weather nor good for cold? There's no actual diversion of exhaust through the intake, or does it alternate through exhaust pulses, i.e. is it an identical situation to "flapper open" in the old system?

It does seem a little cold blooded. Not bad, though need to run with the choke full out for maybe 5 or 10 minutes in cold weather. So why not block the manifold ports off completely? This would seem to be better for summer ops.

I get requests all the time for blocking the intake manifold heated crossovers in the Y-Block intake manifolds.  One of the reasons is simply due to the paint burning at those crossovers on the painted manifolds.  Another reason is to eliminate the potential for carburetor flooding in hot ambient temperatures (Texas and other southern states) that occurs when the engine is shut off due to the manifold being overly hot.  Both reasons are valid but must be weighed against where and when the vehicles are being driven.
 
Both carburetor icing and that transition between where the choke has opened and the engine is still not fully up to temperature are two of the reasons why the intake manifold crossover passage is left open for heat.  When the intake passage is left open, it works best and as designed with the heat riser valve at one of the exhaust manifolds.  Unfortunately those exhaust heat riser valves only have a ten year life expectancy which is why so many older vehicles opt for running without them once the valves start to give trouble.

Lorena, Texas (South of Waco)

Going back on the postings here. Why on a truck would you block off the crossover on the Blue Thunder or "B"manifolds?  Assuming the exhaust system doesn't have a Heat Riser, it's very unlikely that there will be excessive heat, particularly in the area where U live.. Some degree of heat helps vaporize fuel which helps warm ups & avoids card icing.. it's not a race car..     


Paul

Thanks for the option. I will try to wait and get one from Mummerts.  Thanks Joe 

Located in Harford County Maryland