GMC Dude,
Although they all share the same bore, the 153 and the 230 uses the same pistons as the 283, all these trhee engines shares the same compression height. The 250 goes togheter with the 307. Other common parts are the rod bearings for the 153, 230 250 and the smaller 194 and all the small v8 up to 1967. They all have 2.000 std dia. crankshaft rod pins. Also they share the lifters. Of course the 3 7/8 rings also work. Nothing else.
I can say also that the 292 L6 uses the same lifters as the V8, but rod bearings are the same as the small blocks 67 and up, 2.100 crankpin. The 292 at least here in Brazil have a thicker ring pack, 3/32 type, and thereoff the 3 7/8 rings out of a V8 will not fit. Valves from a V8 will vork also, and if You care to install 1.94 intake valves from a 350 in a L6 head You can have some sucsess. 2.02 is too big and will be too close to the cilinder wall, hurting airflow.
Darrel,
The Brazilian 250 EFI uses flat tappets. The cam is ground on the old 849 core, and has a tighter LDA, I'd like to see them using the 882 core, that allows a wider LDA, in a way to make use of the 6.000 long rod.
Greybeard,
I never saw a 151 Iron duke in person(or in engine) to enable myself to say anything about it. I really don't know what are the differences between them and the brazilian 151 and the older 153 from a Nova. But I can say for sure that the 181 head is the older style, with both intake and exaust ports on the same side, but the ports are higher than the old style 153 head. And the intake runners are totally divided by a wall, making them 2 separate runners, different from the 153, where we have just a boss around the head bolt and then the ports merge togheter after the boss. Not a good thing. The 181 bore is 4", the stroke is 3,58"(almost 3.6") the crankpins are 2.300" mains and, strange enough but true, the rod pins are 2,100". I'm buing an 181 engine to me soon, it will be just for research, and as long as it happens, I'll post all I can get. I saw the pistons, they are shorter than a 350V8 one, that has the same compression height as the 151 made in Brazil, I have no idea as if the deck height is the same in all these L4 engines, but if the 181 rods 6.000 long the deck must be taller in the 181. If I'm not mistaken, the 118 was offered in the fiero for some time, isn't it true?? and one more thing, how many head bolts on the iron duke??
