Are they peanut or true oval ports,would they fit a Gen IV block ok?

Please post the casting numbers, b/c like alway's, there are several different ones..

But if the intake ports are wider then they are tall, they are peanut ports. (200 to 225 cc's or so? with most being the smaller numbers)..

Taller then wide are large oval ports.. 235 to 262 cc's or so?)..

AND Vortec BB truck heads are right at 235 cc's and they have 100 cc chambers...

AND everybody know's rect's are just that small radius'ed cornered, great big rect. ports!! (290 to 325 cc's or so?)..

pdq67

The ports don't matter. They will not work on the Gen IV blocks due to the water passages being different.

I disagree: I have Vortec L-29 Gen 6 heads on my MK IV 454 boat engine. There is NO PROBLEM with coolant passage alignment when using Gen 6 heads on a MK IV block. The problems are when you use MK IV heads on a Gen 5 block. You can bolt the L-29 heads right onto the Mk IV block, using a MK IV head gasket. You have standard MK IV water flow, "series cooling". IF you drill three holes in each deck surface of the block, you can use Gen 5/6 head gaskets, with the benefit of parallel cooling water flow.

The L-29 heads have a TERIFFIC exhaust port, but the intake could use some help. It is a "large" oval port, though.

Casting number is 10114156.