i have a long block 454. large oval heads (recent valve job) the compression is alittle low. I would be willing to say it needs rings and that would greatly help the situation. I havn't torn into it yet and quite honeslt was planning on rebiulding it over the next few months but if you are interested i have it. Its a gen iv and ran in slat fora 15 years but it ran up until a few months ago when i pulled it form my boat because it was runnign funny. e-mail me if you interested.