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engine swap, tying info together


NAXJA Forum User
Atlanta, Georgia
hey all,

i have an old tired RENIX 4.0 in my 1990 and i have been saving to build a stroker to swap in. i was planning on using a renix block for a 100% straightforward swap, but i have the opportunity to get an HO motor for free, so i decided to take it, and stroke it possibly.

ill be using the HO block and head, renix everything else

i have been reading scattered info in hundreds of threads discussing compatibility of heads, intakes, etc and i want to tie it al together here hopefully and answer some questions

1. intake: i planned on using the renix intake for simplicity reasons, but i have read the ports dont line up perfectly with the head...how bad are they off?

2. exhaust: i have read that the HO STOCK header will fit, but aftermarket wont cuz of the renix intake manifold, so ill probly use a pacesetter performance header for renix era 4.0s

3. sensors: i plan on relocating the coolant sensor up to the thermostat housing..but im kinda lost on the knock sensor, what do i do with that?

4. head: i will use the HO head, probly get valve jobs, etc on it, but it also comes back to the question about the ports lining up...

im not asking about how to build a stroker, but simply the little things that will make this job annoying.

in the end, i might just swap in the HO and stroke the RENIX and put it back in cuz of the knock sensor. do you think ill get more power that way?

The Renix intake will run just fine on the HO head, but the ports will be a ways off on the top. I think last one of those I did the gasket needed to be trimmed a little and then I put silicone across the top as the sealing area gets rather small. This goes along with elongating the alignment dowel holes on the intake. It sounds like a kludge but ran great on my stock displacement engine.

The knock sensor will work anywhere you can bolt it on the block, detonation noise travels quickly through iron so anywhere should be fine.

The Pacesetter Renix header should work for you, that's what I ran but it was a long time ago, assuming the part's the same still.
I am doing a 100% Renix stroker this summer, I am not using the HO Head because I have my Renix head ported and polished with larger -unshrouded valves. I have a ability to have made it all HO. But I have the head in my "stocker" with all my external mods and it runs great. It will only get better with more displacement and a slightly better cam. Its my belief that I can get this motor more than enough airflow in the RPM's it sees, nothing above 4000. And thats really the only drawback I see using the renix head and intake... YMMV. Good Luck