n/a precups vs turbo precups

[Vin82k3500]

I have an early model 6.2 block I am gonna use as a base for a build up with 6.5 heads it is the high nickle 82 block I am planning to get the stud kits and main girdle kit as well as upgrade harmonic balancer banks turbo system possibly intercoller db2 4911 pump wondering if anyone has calculated figures on the diference in power and fuel economy in the 2 I know obviously the na precups get better mileage and the turbo precups make more power but more concern than the power and mileage the egt wich is higher I haul cars wood rvs ect local runs power and speed is no issue high way I would like a little more but would like to not compromise my fule mileage when empty or the durability of my engine:confused:

[john8662]

smaller precups do fine on engines up to 250 HP. Bigger HP numbers the larger cups perform.

I like the mid-sized turbo cups, good for power and economy. n/a cups are basically what the light-duty 6.5 turbo heads have. They run pretty good and mileage well.

[Robyn]

IIRC the 82 C engines had real tiny ports in the precups.

In later years the cup sizes were all over the map.

The "T" cup was a nice compromise.


Missy

[Vin82k3500]

the hads I have are from a 93 6.5 from a 1 ton non egr will look into those t cups Robyn and the sizes mid range will be good John I want to keep decent mileage and 250 is the most I will probably be looking after I want to keep the engine strong thats why I was wondering if the smaller cups held more heat in the head than the larger ones

[Vin82k3500]

While on not of parts does anyone know much about clutches my question is that I am running an nv4500 from a 92 that was part of a conversion kit with mechanical clutch linkage as oppodrf to hydraulic wich I perfer the manual linkage btw but this weekend past I wanted to replace my clutch but when I went to my local parts store to order it I ran into a little dilema the listings all said it had a 12 inch clutch but it only measures 11 inches my nv4500 conversion is for a jeep not sure if that is a factor but I see no room for a bigger clutch :(:confused:

[dixiepc]

While we are talking about pre-cups, does anyone know if C-code pre-cups were the same throughout the different year models?

[sctrailrider]

One of the things I have found on different cups through the years is if you don't know if anything has been rebuilt in the past (the head), the "real GM cups are NOT magnetic, they were made out of inconel, (spelling ? ) the cups found in some off shore aftermarket heads look the same, have the same markings, BUT ARE magnetic ?? I can't say for sure but I would think that a "real GM, GEP,AMG, etc cup would be non magnetic ?? I have several different sets here and have done some checking and someone correct me if I am wrong but the aftermarket cups are more prone to cracking no matter what style they are??