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New (to me)motor, swapping a 302

N

NW Redneck

New member
Due to someone who shall remain nameless to protect me, my engine block was not drained properly & subsequently cracked. OMC 175 setup. I've recently picked up another complete 302 to make it live again. This motor came from a truck at some point. There's a few differences. The new heads are 69cc vs my old 58.2 Would like to keep the originals as they are in good shape and will give higher compression. Also the new engine comes with a 4bbl intalke with a vacuum secondary Holley carb, and also has a roller cam/lifter setup. I'm thinking of keeping these as on teardown they all look in great condition. As this is my first major swap that was not just a same for same I have some concerns. Is there any jetting changes I should be making? How can I determine what length pushrods I'll need (the roller lifters seem taller). And are there any other things I'm just not aware of? Should I stay with the standard 175 firing order or change to the 190? Any & all advice greatly welcomed!
 
My 302 is a 1976 190 HP. The difference between the 175 and the 190 is the firing order and the roller cam, which is a GT40 head. I believe they changed the firing order to handle a problem of some cylinder getting hotter and blowing out more often - I don't know that it increases performance. Of course, that would mean a change of the cam. I am not sure about the size of the lifters but would think they would be different.
I had a two-barrel Holley with .071 jets and it always seemed fuel starved - always having to pump the throttle, etc. I put in a four-barrel with .095 jets in the primary and it runs much better, as I had a larger 4-barrel intake manifold, as well.
I have done a lot of upgrades to my 302 and have a lot of experience.
 
Here is a write-up from Grok on his estimate of the horsepower from the upgrades I made. It is a pretty interesting read. Grok has helped me a lot for any questions I have had and is free. But it doesn't replace the experience of the pros on this website.
 

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  • Groks estimate of the horsepower of my Ford 302.pdf
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Thank you very much for your reply Neil. I am not looking for big HP gains so much as a slight boost in performance and an overall reliable powerplant, This boat will be used for cruising up to our cabin with a little skiing etc, once in a while. Not looking to be a speed demon. Just a little over my head and looking for advice from those with more experience.
 
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