SB

It will take more compression and more rpm's.

Remember, a HP500 makes it's power around 5200 with Dart intake, rect heads with bigger 2.25 valves and 502cid. Oh yeh, a pretty good (.600" lift) hydr roller also.

Just to put it all in more perspective.

Airpacker

Trevor, long time no see. Call Raymond at RR and see if he has any decent take outs. He had a nice pair of low hour 500efi's, fully dressed less headers for around 20k CDN when I last talked to him. If you plan on making 500hp with the 454's, its gonna take some compression and thusly, premium all the time. Prolly need to do some head work or swap em out, rollerise it etc. Might be cheaper in the long run to just deal what ya got and buy some used 500hp's or efi's. If you descide to build what you have, do yourself a favour and call Mike at Active Engines ( 905-855-1244) before you do anything.

As for your question about using RR for service, I think you will find they come HIGHLY recommended by anyone who has dealt with him in the past.
There's a reason people around these parts leave their million dollar boats in his care.

Thunder Struck

AP
I've been away for a while building a home and farm. Been VERY busy. I really do not want to get into an engine swap. I know what I have and they have treated me well. The old girl is only going to go so fast anyway. Right now all I have to my knowledge is a bearing issue and some rat a tap tap from around #6 or #8. Still runs and everything.... no total destruction like the Mirage. The other still runs. We were planning on going to Chief this weekend with her. Trailer to Orillia (stop at R&R) and idle out to the island for the day possibly the night, but now they are calling for rain so that may be off. Hope all is going well dude.

WH