Long time lurker, first time poster here. I’ve been through all the 2.5 posts on the forum, and hope someone with SD4 experience could weigh in. What’s your thoughts on the engine? Taking cost out of the equation, would you consider the SD4 a viable replacement for the Iron Duke and usable on the street?
I have an 80 Spyder I’m about to have professionally restored. It has the crossflow Iron Duke, which I'm investigating swapping out for a mild, low-compression SD4. The car would be primarily used for weekend driving.
I realize this isn't the most cost-effective transplant, but I’d want to keep the car as close to the appearance of stock as possible and retain all the accessories (particularly the a/c). My hope is that the SD4 could be a drop-in replacement. My days of wrench twisting are long behind me, so the job of rebuilding and fitting would be the responsibility of the restoration shop.
Having said all that, I’m looking for a little feedback on feasibility. Here’s what I’m looking to accomplish:
- -150-200HP
-Runs on 93 octane pump gas
-Has a smooth idle
-Allows me to keep my stock equipment
-Fits under the hood without requiring a hood scoop
-Has good reliability and longevity
Is this doable? Right now, this is all just a fact-finding mission for me. This is not my area of expertise, and for all I know, may be completely out of the realm of possibility. I understand SD4 parts are few and far between. So here’s one last question: I know if I decide to rebuild the Iron Duke, anything beyond 120hp is not going to be possible due to block and crank issues. Is it possible to use an SD4 block and crank with the Iron Duke top half?
Thanks for indulging me.