Mini starter Heat Soak or something electrical

My New World Block 472 Hemi has New 2 1/8 " TTI Nickel Plated Headers with a Denso Mini Starter. This starter was listed on the TTI installation instructions sheets as one of the 5 starters that will work with the TTI Headers and Schumacher Engine mount combination. The existing starter was on the previous Wedge Engine that was in my 1965 Belvedere I and it performed perfectly. Just to be safe, I had the starter checked and nothing was found to be wrong, but I still had it totally rebuilt anyway. The starter work was completed by a highly competant local starter company here in town. I have a thermal insulator wrap around the rear portion of the starter where the solenoid is located. I fabricated a starter shield out of 1/8" aluminum, but when installed the starter shield touches both the header and the starter as there is next to no room between the drivers side header and the starter. The header and the starter are RIDICULOUSLY close to each other. The engine's total timing is set at exactly 32 degrees per the directive from my engine builder. The starter engages perfectly with no hesitation when the engine is cold, but after driving the car for 30 minutes or so in hot, humid weather and shutting it off, it will not immediately engage upon trying to re-start the engine. Upon turning the key, it completely hesitates for a nano-second and then it reluctantly engages slowly turning over like the timing is too far advanced. I spoke to ( 2 ) TTI engineers that both said they are stumped, they offered very little valid suggestions and stated that I am the only person ever to call to complain about this problem. BULL ! ! ! At the TTI engineer's suggestion, I removed the aluminum starter shield and it still has the hesitation when the engine is hot. I am out of suggestions. Could I possibly have an electrical problem totally isolated from the starter, such as a bad ignition switch, bad starter relay or a bad connection at the firewall terminal block ? Any thoughts or suggestions are appreciated.

Thanks Moparts...

My very little used 440Source ministarter does this, I emailed them and asked about it and they said it needed a new solenoid. I've yet to try the suggestion.

either (1) heat soak prob (2) bad cable/not enough current (3) too much initial (4) eng too tight when hot. I'd start w #1 then #2

What starter did you get? Some of the aftermarket Chinese built units are not of very good quality.The factory units are the way to on this part
I have seen these starters get so hot that the sticker melts and peels away like a scab and still start the car.Robert brings up a valid point about battery cable size and quality of the cable are very important.I have a factory Dakota starter on my car that has been there for two engines and hundreds of hot starts in the staging lanes with the engine at 230 degrees and 11.1 compression.
I use welding cable from the trunk to the starter and have no issues since the cable change.
Gus

i had same problem on my challenger let it sit and cool off and it would start. one day it finally gave up and end of cable came off bought new biggest cable i could find have had no problems since ozz

I had the same problem with a new 440 source starter. Put my 45 year old stocker back in. No more problems.

Thanks for all of the comments.

Here's the deal.. the Denso starter that I am using came on the .030 over 440 Wedge engine with 12.5 to 1 compression that came with the car. I believe that this starter originally was purchased from Summit by the former owner of the car and the Denso Part Number is 17573. This Denso Part Number cross references over to the Mopar Performance Part Number of 56027702. This 56027702 starter number is one of 5 that TTI dictates that must be used with their 2 1/8" headers that are now on the car. This starter, over the time of 4 years that I have owned the car never failed to start the Wedge engine whether the outside temperature was cold or hot. As noted, the Wedge engine ( an all out race engine built by Compu-Flow ) was a 12.5 to 1 engine and this New Hemi is only a 9 to 1 engine ! In duplicating the 1965 Race Hemi ( A 990 engine package ) theme, I added a terminal block on the drivers side fender well that I purchased from Jim Kramer of Kramer Automotive. I then ran # 2 welding cable from the terminal block down to the starter. When I had the starter shop check the starter, again they found nothing wrong, but since the removal of the starter with the 2 1/8" TTI headers is an ABSOLUTE pain, I had the starter rebuilt, just to be safe. Bottom line, all that was changed other than the engine was adding the terminal block and adding the # 2 welding cable with crimped on cable lugs from the terminal block down to the starter.

Any more thoughts or comments ?

NAPA sells an insulated blanket for starters. It helped on mine.