View Full Version : New 532 BBF need help with cam selection in z25

08-03-2017, 10:48 AM

my 89 Z25's 460 let go on me and i have replaced it with a 532 with aluminum heads. the motor did not come with a cam and im having the hardest time deciding between a roller cam set up or a flat tappet. I have heard horror stories about roller lifters not lasting, push rod angles not being correct and trashing the valve-train, and at the same time i've read horror stories where people are trashing flat tappet cams once a year.

so im really just looking for a couple opinions on what you would do, im completely open at this point as to which way to go flat tappet or roller.

the engine is brand new never started, with roller rockers, eldebrock intake, and will be running an 850 carb (most likely quick fuel).

thanks in advance for any help.

08-03-2017, 12:54 PM
I say go roller, I have purchased quality stuff and haven't had a problem with my engines.


08-03-2017, 01:25 PM
thanks for the input, is there a specific brand you have had luck out of or a brand to stay away from?

08-03-2017, 08:43 PM
I just did a quick search on the Comp site, but nothing for marine use listed.....
Maybe check w/Crane.
I think most of the major cam companies will build what you want, you might check w/both.

08-07-2017, 02:08 AM

Signup on there and look around there are a few guys with marine experience. One guy is Paul Kane another is I believe The Mad Porter. Great place, Great guys and the only place to get Ford 385 series BBF help and advice.

08-09-2017, 10:14 AM
Thanks for the advice, I signed up yesterday. I actually ended up buying a full roller set up and i found a great engine shop in Concord, NC which isn't too far from me. im am having him break in the engine and tune it on the dyno over the next few weeks. this guy is set on having me run the 750 Holley that came off my old dead 460, which doesn't sound like enough carb for that big motor...............but i guess we will see on the dyno.

the engine builder claimed with a roller cam and 850 carb these engine consistently produce 650hp/700tq every time he dynos one he builds, so i guess ill be able to call his bluff if it doesn't. ill post up the results.

Pat McPherson
08-09-2017, 12:42 PM
I have a 750 on my stock 435HP 502 and I know Merc ran 800 on 500HP 502.
I have a bud that runs a 950cfm on a 600HP 509 but that's up to 6000rpm.

I think your engine will need more flow than 750cfm above 46-4700rpm.

08-09-2017, 05:59 PM
I agree, I seemed to be running out of air w/my 509 BBC (800 CFM Holley), a member recommended I contact
Patrick James @ Pro Products Racing Carbs (727-490-5717) who built a 950 custom carb built specifically for
my engine that would flow at least 840 CFM. It seems Holley's nomenclature isn't very accurate. I've only run it
a couple of times and have picked up over 200 RPM..

08-10-2017, 09:20 AM
Tell us about the exhaust you will be using.


08-10-2017, 10:37 AM
Everyone thanks for the advice and help

On the carb i was thinking the exact same thing................i wont argue with you one bit. This guy swears he can make the 750 work excellent so i figured ill give him a shot, and he even offered to throw one of his 850's on it on the dyno to show me the comparison between the two. In the long run of things if it needs a bigger carb ill get a bigger carb. Truth be told this is way more motor than i need, so if the 750 operates fine just holds back a few ponies i would be ok with it, but it its going to be an operational issue i wont have that.

The exhaust is just the factory through hull exhaust, the heads (i forgot the make) are made to work with OEM BBF exhaust manifold. also it will be dyno tuned with the exhaust im using hopefully with in the next two weeks. If you want take a look at the guys website im getting the cam, lifters, rockers and pushrods from, he is also the one dynoing tuning it. the owner of the company is a friend of a friend and he built and tuned my fiends 460 in a spectra and it runs fantastic. i wish i could say my engine was built by him, but unfortunately it wasn't, it came out of a separate company in CA.
here is his companies website.

Honestly what im really looking for here is a little more power than my old worn out 28 year old 900hr 460, and a turn key reliability is the big ticket for me.......well as much as a carb'd big block will allow anyway. I love this boat its smooth, looks great, sounds great, and it turns heads, so if I can get her to operate as good as she looks ill be all smiles!! i spend 2-3 days a week on the local lake on my boat, and with the Donzi down our 28ft regal and seadoo just aren't cutting it :rolleyes:.

08-10-2017, 06:12 PM
the 460 head on a 532 has some decent intake port volume, it NEEDS food... with that said *I* would think a 950 would be more efficient overall and respond better to jetting/mixture changes :pimp:

08-10-2017, 06:24 PM
I was wondering if you were aware of these exhaust manifolds by Hardin:


These manifolds have been the "go to" manifolds for BBC's for many years.
Originally supplied by Gil until they failed during the recession, Hardin has
added these BBF manifolds, which has the same port spacing as BBC's but
a different bolt pattern. These manifolds substantially outperform the old
OMC exhaust manifolds.

08-11-2017, 09:42 AM
well now...........sounds like i will need a bigger carb, there is new in the box dominator 1050 on my local craigslist for $450, should i look into that or is that too big.


I really like the hardin marine stuff. i had it on my 1966 skisporter's 408 stroker, and on my 77 Spectra day cruiser's 460 which got stolen off the boat in winter storage:mad:.

anyway i am a big fan of them, and when the time comes and these oldie goldie OMC's are toast ill have a set!

so im sure as you guys can tell from those Three dreadful letters my boat is equipped with the dreaded OMC Baby King (dog clutch, shift in lower unit) out drive. unluckily but luckily at the same time when i first got the boat 6 months ago the drive exploded on me, admittedly it had no oil in it and it was totally my fault. luckily i found a local older gentleman who is an OMC expert and he was able to rebuild my drive and alight the shifter cable properly and now it is a properly working drive. i guess my question here is, how long do you think she will hold up? i do not drive my boat like an idiot, we do not ski behind it, i just cruise with her at the end of the day its a 28 year old boat im restoring not a beater to me.

08-11-2017, 12:14 PM
well now...........sounds like i will need a bigger carb, there is new in the box dominator 1050 on my local craigslist for $450, should i look into that or is that too big.

No offence to anyone, just my 2 cents, but the engine builder that you wish built your motor, and the engine builder that is going to dyno your engine swears he can make the 750 work....and he is willing to install a bigger carb just to show you it's not going to work any better.

I realize others have given you their experience with what worked for them, but I'd wait to see how well the engine builder can make the 750 work. If he can't make it work and you need a bigger carb, you can buy one then, but I'd go with what the engine builder suggests first.

08-11-2017, 01:19 PM
fair enough and im definitely going to give it a shot on the dyno