i'm new here and I need some help

[black rocket]

Okkkk, 1st gear you can easily hit 40-50 mph. As to your tranny issue is concerned, did you change the gear oil? Sounds to me like you may be running with degraded oil based on the fact that it's hard to shift unless synchro is goner.

Why don't you post a pic of TB & dynamic chambers as what boosted said makes a great deal of sense.

Have you done a compression test to see the condion of them engines. As you mentioned that 1st is slow. Even seals are blown it will run but, much slower and hard to start.