I do not know compression ratio so that seems like it is going to be a bit of a problem......

If you have a 500HP 454 I would bet you are running 9.6+ comp. I would not bother with a 174. You will not be able to run enough boost to get the added HP you are after. In my opinion the 174 should sit on top a 454 with 7.5-8.0/1 Blower pistons with aluminum heads. If you are going to pay upwards of 2K for an intercooler just start with a 250 and put an intercooler under it. Start with a Bullet proof bottom good heads and a good exhaust then if you start with a 174 you have options. 250, 420, etc

Not rying to build a motor, infact, trying to stay far from that. I guess maybe I will spend the money on cosmetics....

You asked if it was worth it, I would have to say with the right set up yes.

-More speed, prob 10-14 mph on a boat your size
-More torque = much higher cruise speed using the same fuel
-Bang for buck, besides nitrous which sucks on a boat you can't do better

Of course there are precautions, however if you posted another thread asking what to watch for or changes that should be made to just a 500hp you would hear stuff that would keep you from sleeping at night!

I wouldn't be afraid to go that route again, just some basix rules

-Reduce timing a few degrees, you can always go back
-crossover cooling, you should have it anyway IMO, clean simple setup
-relocate temp sensor, very easy fix
-maintenance and cleaning of ignition system twice a year, takes all but an hour.

For added insurance ad a knock sensor and meter from summit for $150 if you like.


What do you have for speed now?

[QUOTE=4bus;3268808]You asked if it was worth it, I would have to say with the right set up yes.

-More speed, prob 10-14 mph on a boat your size
-More torque = much higher cruise speed using the same fuel
-Bang for buck, besides nitrous which sucks on a boat you can't do better

Of course there are precautions, however if you posted another thread asking what to watch for or changes that should be made to just a 500hp you would hear stuff that would keep you from sleeping at night!

I wouldn't be afraid to go that route again, just some basix rules

-Reduce timing a few degrees, you can always go back
-crossover cooling, you should have it anyway IMO, clean simple setup
-relocate temp sensor, very easy fix
-maintenance and cleaning of ignition system twice a year, takes all but an hour.

For added insurance ad a knock sensor and meter from summit for $150 if you like.


Ditto add the blower ,change the carb, re-prop and run 5 lbs boost all day long :drink::drink::drink:

174 = heat pump. an intercooler just increases boost and heat, not removing enough temp to make it worthwhile on the smaller blowers.

I had one on my old boat and loved it. no intercooler, nickerson carb, inconnel valves, 5lb boost. 10 mph increase on a single 25' boat. I didnt change fuel lines, but did add an electric "helper" fuel pump to supply the stock pump. then added boost and fuel press gauges just to keep an eye on everything.

Small blowers do turn fast, and create heat, but they work. Just look at the 525SC. Tons of guys ran them for many years, spinning the crap out of the little blower with small pullies making 7lbs. In my opinion, the key is good parts, good gas, and a good tune to keep it alive. Ive got a buddy making 825HP and 850FT lbs with a small 256 weiand on top of a 598CI. 3PSI, no intercooler. 3 seasons, no issues. Sure a 10-71 would make alot more power with added boost.

This guy could bolt on a 8-71, run 8-9PSI, but the question is, is the rest of his engine able to support 700HP? Crank, rods, head gaskets, etc? How about his drive? Usually a stock motor can handle 4-5psi. And bolting on a huge blower on a small motor setup to make only 3-4lbs, will take lots of HP to drive, and probably not make as much torque thruout the RPM range as the small blower.

If purchasing new, i'd spend a couple more bucks and go with a 250/256 blower. If you should grenede that 454 block, and end up going with a 502, the blower will still work on the bigger motor.

Well I see alot of differing opinions here. And there is alot to consider...I thought this would be a simple bolt on and go.

I appreciate everyone's input!

I am confused at the one reply that said an intercooler would create more heat.....i have built serveral buick grand nationals and the better the intercooler the more power and never was a heat issue. I know it's a car and turbo, just in my mind it is confiusing.

I have been in performance boats for about 10 yrs now, not one of which had stock power, but I am thinking I still have a lot to learn!

I think what he meant was the intercooler is a restriction. Usually you would lose about 1psi of boost by adding the intercooler. To get the boost back, you'd run a smaller pulley, which will bring the boost up again, but also some heat. However, I would think the intercooler setup at 4lbs, vs non intercooled at 5psi, would net around the same HP. Just the intercooled version should be safer. if that makes sense.

The intercooler with a larger blower seems like it would work better, because even though you lose some boost from the intercooler, you can run a smaller pulley, make decent boost, and not be overdriving the blower.

I like the idea of choosing a blower and blower ratio, in which you do not NEED to run a intercooler. Say you go with a 256 blower on your 454. And the compression, fuel supply, and timing allow you to run 6psi safely on 93 octane all day. Then, you add the intercooler to cool the charge. Your gauge will probably show 5psi then. Your making as much HP, if not slightly more than non-intercooled, but should be very reliable. Should your water feed to the intercooler get plugged up, or you get a lesser grade of fuel, its not gonna detonate itself to death.

Keep in mind i am no engine builder! We really need eddie young to chime in on this topic...Eddie???

Also, keep in mind that for a 174 blower, to make 5psi on a 454, will probably need to be driven somewhere around 2.2:1 ratio. Meaning that at 5000RPM, the blower will be turning say 11k rpm. With a 250 blower, you might only turn the blower around 6500rpm to make that 5psi....Larger rotors turning slower, means less heat. I believe the weiand 177 is rated for 12000RPM or something like that for max speed. Plus turning them that fast reduces their life span.