Though the 454 in my Rinker 236 runs well, I'm trying to get my ducks in a row for when it comes time to repower. Probably going to go with a new base 502 engine (435hp) from 1800runsnew.com. I need suggestions for an intake manifold, carb, electric fuel pump and headers if you guys feel aftermarket headers will benefit the 502 compared to the stock 454 manifolds. The boat also has Captain's Choice exhaust. The boat runs an easy 60mph with the stock 454 and Mirage 23p prop with 4 adults and a full tank of gas. Any guesses on what top speed would be with the 502?

I have a question. If your going to spend $6K on a long block why not get one from one of the builders on here that can get you an extra 200HP for roughly the same investment? I recently rebuilt a 454 for a customer that made 40 more HP than thier base 502 still using penut port heads.

If 502 is what you want go for it. I'm just curious.

Why dump the money into a block where life ends at about 500 inches compared to one where life begins at 500 inches? The 502 gives me room to grow if I so choose. I'd rather pull my original Merc 454 out as a running mill and stick it on the side and start fresh with a 502 that has a forged rotating assembly right from the get go.

I am guessing 3mph. You better plan close to $8k after you buy manifold, carb and what ever else you may need. Most new 502's come with a fuel pump boss, but no lobe on the cam. I took brand new 502's apart and put Bob Mandra cams in with lobes for the fuel pump. Been there done that times 2.

If the block has a mechanical pump provision, it would definitely make sense to go with a cam from Bob with a mechanical pump lobe.

Can Bob M. build it , yes he can !!! Take all the worries out of it and give him a call , you'll be pleasantly surprised and money ahead !

I would ask Gordon (smokin gun) about 1800runs new. He had a horror story about them and I would believe every word he says about the experience.

OK, that's what I was looking for. I hear people wanting to upgrade to a 502 because they think that is the only way to get more power.

Your chances of getting a long lasting, trouble free reliable engine from 1800runs new is probably 50/50 from what I have read.
Lots of threads on here about them

Is that in regards to their rebuilt engines? If I bought an engine from them, it would be the new base GM engine. I should be fine with a new engine since they are the supplier, not the builder of the GM 502s, correct?