alright so we have been using the ln2 and as many of you know i ahve grenaded a ton of them and in big ways at that so i am not afraid to try some off the wall combos..... but now where we are using a third gen they are a lot wider in the front frame area. Our class will let us use any chevy motor as long as it is four cylinder 8v and 2.5 or less. so this leaves me with two options. we can either keep trying new high compression hopefully stay together 2.2's or what about an iron duke 2.5 out of an s-10. length wise it will fit in the engine bay and i will be building mounts for it anyways. so this is really the wrong forum to ask but do you guys think i will have many disadvantages with the 2.5. for the tour we are running it would raise minimum weight from 2200-2500, and for the track we race at weekly it would raise weight from 2200-2350 because of the bigger displacement

Do the heads have to be production heads? If not go with the Iron Duke with the Super Duty 4 head and intake. If not and you go with the Iron Duke, the Cross Flow heads flow the best, but can be prone to cracking, if the cooling isn't up to snuff. IIRC, '79-'80 Monza/Sunbird RWD applications were the cross flow and had some decent durability. I think it was when they put them in the S-10s, they went to a lighter casting and was worse on the FWD applications.

With some valve seats and custom pushrods, the cross flow heads will fit the smaller 1.875" Olds intake valves for a little more flow. The exhaust were about the same size.

Isky Racing Cams has some good racing cams for the Iron Duke.

You could also do like the ARCA Trucks did and use a aftermarket Small Block Chevy head on a redrilled SD4 block.

It also depends on the track and how well you chasis handles the additional weight. I still think you'll be better off with the 2.2L and J-Body.

ya they have to be a production head, compression of 12:1 or lower and .450 solid lift cam are basically the engine rules