How is a 174 blower going to do on a gen6 454 with hp500 heads. Will this set up work? Anybody out thier have this? Engine temp/oil temp? How much boost would u recommend. Any input would be a help

Blower is small. Wouldn't run more than about 4psi. It can work, the old 525 Hawk engines were similar. If you haven't purchased it, I would strongly suggest going to a 250 blower at minimum. Small blowers make lots of heat.

the 174 blower works great on a 454 with the 500 heads the right cam will add 100-125 hp 4-5lb boost

It only works decent if the motor is built right for it. Imop go with a 250, make more power run better, cooler and it will be easier on the pistons and exhaust valves. Less heat.

A 250 would be better, but you should still be able run 4-5lbs of boost with the 174 as long the static comp ratio is around 8.5-8.75:1.

HP500 heads are nothing special. Just GM rect ports like a 454mag with slightly bigger valves.

Run a 140* Tstat or less.

If you have "added" rectangle port heads, I assume you did not have them before. Most oval port Mercruiser 454's had cast pistons and crank, and small rod bolts. The cast pistons will not tolerate much boost and will definitely not tolerate boost AND octane-related detonation. The rod bolts should at least be replaced with aftermarket ones (or just get a set of reconditioned 7/16 rods).

4 to 5 psi is your upper limit with the 174. Above that you are whipping up more heat than you're helping.
An 8.5:1 454 at 5psi with rectangle port heads and a good cam will take you over 500hp (you'll definitely need to upgrade your exhaust if you go above 3psi).

I run 6psi with 177 blowers on 9.5:1 454s. The extra compression is helpful and with my alum heads it works quite well. I wouldn't try that with iron heads. 8.75:1 would be about it with iron running 5psi and 93oct.and a nice close quench distance. My closed cooling gives me about 150f water temps and 210f oil temps. 30* of timing all in, 11.6afr at wot. In hot humid weather there is a noticeable (2mph) loss in top end perf due to small blowers. I'd much prefer 250s but would not hesitate to do the 177s again if that is what presented itself. My rotating assembly is all forged. I broke a nodular cast crank in early experimenting with the blower motors.

Like others have mentioned, the 174 is a rather small blower that will cause more heat in the intake charge. As others suggested, if you haven't bought the blower yet it would be in your best interest to find a b&m 250. That or a weiand 256. You'll be much happier and there will be less chance of damage to your motor. Especially if your motor doesn't have good parts like iconal valves, a good rotating assem., etc...