IMO, the 177 is maxed out on 454 and a 250 is maxed out on a 502.
Higher compression pistons will allow you to spin them slower and make less boost, so they can work an larger ci engines. Its just not the preferred method.

In the end, a supercharger forces more air in and raises the effective compression ratio. If you start spinning the smaller SC's too fast, they will just make more heat and increase the risk of detonation.

i think i will do the conversions 454 - 525sc when freshing up the engines maybe this year. anyone knows a company to sell all the stuff i need and gives good support. i always have a lot of questions and not all companies like this.:argue:

I would like to know more:

I have a 95 454mag and looking to do the same thing.
I have a complete take off coming but am a little nervous about the final compression.

525sc w/5.5lbs boost and 7.5:1 compression is at 10.31 final.
Mine w/5.5lbs boost and 8.6:1 compression is at 11.83 final.
That is like running 8.5 lbs of boost on the 7.5:1 engine, minus the extra blower heat.

Now given I am running the stock Iron heads, is it going to detonate?
I don't really have the $$ to spend on a cooler, maybe I can go with methanol injection
for an extra level of safety.

Or do I need to find a big enough pulley to drop it below 4lbs of boost.
(4lbs will be at 10.94:1 final)

What are your thoughts on this?

My dynamic compression is 12.5:1 w/ 5psi and 9.5:1 pistons. No detonation evident after a season of running hard and complete teardown this winter. I run aluminum heads, 30* timing from a V-6 module and 11.7afr and 93 octane. I also dropped 2-3 numbers cooler in spark plugs. No intercoolers. Seems to work. You will be a little closer to the edge with iron heads but I would give it a shot anyway. Other things that would give more insurance; wider ring end gap on top rings, cometic head gaskets, arp head bolts and inconnel exhaust valves.

I have been there, done that with the 454 to 525sc conversion, and it workded out great. I started with a 454 mag., installed forged aluminum pistons with a compression ratio of 8.25/1, installed edelbrock marine rect. port heads with good valves and roller rocker arms, a crane hydraulic roller 731 cam and lifters and crane roller rockers. I then installed a weiand 177 with superchiller intercooler and custom built boost referenced 4150 style carb.

I have run this for a season(probably 60 hrs) and it is rock solid. It sound like huge power, even though it isn't, and does a great job of delivering a reliable 600+ HP.

I unfortuneately got the speed bug and am finishing up a 609ci motor that will be in the 900+ range.

we pulled the 525 out this last weekend. the only parts I am re-using are the headers, distributor, and msd ignition. I would prefer to sell the motor complete, but might separate the induction package(carb, intercooler, blower, intake), heads, and then short block.

pm me or call me if you want to talk about it 405-850-0515

sam

I think you will be fine. I ran 8# of boost on my 525sc without a chiller and it was fine and thats with 35* of timing and 92 octane. The engine had 300+ hrs with that combo and was still going strong. You could run some extra thick cometic head gaskets to lower the CR a little.

Did you run that 454 on a dyno Sam? If so, what boost were you running to get the 600hp?

Edelbrock Oval RPM marine heads, 525sc blower with factory Dominator, 525SC cam, 8.5:1 comp, 500 EFI headers. Pretty good power for a super mild combo.. :ernaehrung004:

That is a nice motor.

Tyler Crockett put together a sweet package for me. I went the whole enchilada with Brodix heads. Never on dyno, but a sweet package perfect idle and lots of power.