ok im selling my fourth gen and i just happen to have a third gen in my driveway with no motor (who doesnt) and well i love my lt1 motor i mean i have over 140k miles on thing and ive had it over 160 with room to pull on my t56 with 3.73's anyways there is a local junkyard that sells these motors pretty cheap i also just happen to have an lt4 in my closset and also an extra set of lt1 heads well i was talking to this guy at the yard and he did an lt4 converition on his vette and he was telling me that the lt1 heads flow better ported than the lt4 heads out of the box also i have seen motors with these stock heads ported of course in the 900hp range

random thoughts of an insomniac :lala: :lala: :lala: :lala:

 

 

LT1 iron heads with serious port and valve work will outflow stock aluminum LT4 heads. There are several flowbench result tables on quite a few web sites that indicate that. However, properly ported LT4 heads will do even better, and aftermarket heads are yet a step beyond those.

900HP? Is that Japanese horsepower, or real horsepower as measured at the output shaft in the real world? I seriously doubt that 900BHP would be sustainable by an LT1/4 without some significant boost pressure. That being the case, head flow rates are less of an issue, since the boost will overcome a lot of the flow restriction, and a lot more attention needs to be paid to the case and rotating assembly to withstand the cylinder pressures required to make that kind of power in eight 4" holes.