ran the cleveland and ran great. high compression with dome pistons and a 268 comp cam. great little 4wd setup. but the 351m doesn't have much compression and hard to compare either if compression isn't the same. On the 4v heads I would build a 400 motor instead of 351m. big heads need some cubic inch. If you go 351 cleveland the headers will be the issue for you applicaiton and gonna need to get a different flywheel housing for small block or small block c-6 tranny auto. really like the cleveland motor. but the 351m will run well also if same effort is applied.