Well, it looks like I have to yank the engine out yet AGAIN to fix the rear seal. I've had the engine for going on three yers, and here I have to pull it for the second time for this. I really want this to be the last time till the thing blows or whatever lol.

Anyways, I figured I may as well git rid of the flat tappet and go retro-roller since it's out. Don't get me wrong, it runs very strong as is, but I like the benefits of rollers.

I have the lifters and pushrods, but still need spings most likely and maybe additional machine work on the heads to accomidate the additional lifts that roller cams provide - which takes me to the topic of this post - hyd. roller cam.

I currently run a XE274 cam in it now, setup is in sig. Dart Iron Eagles, 200 cc intake runners, 70cc chambers. Around 9.5:1 compression using -16 cc dish pistons and 3.75" stroke crank and 5.7 rods. RPM air gap-like intake.

That combo was dynoed with the setup above, torque peaked around 3400, and HP at 4200. Of course that's before accessories (alt,ps etc) and my smaller exhaust etc.

What I'd like to get from a roller is max hp (and more of it) around 5300 and tq at around 4500. I was thinking the XR288 retro roller, but I'm open to any other suggestions!

 

You might have clearance issues between the cam lobes and rods.

 

Hmmm.....I really didn't count on that happening, but it's def. a valid point. That sparks up a dilema then. I know some brands sell a small base circle cam that helps if rods hit the lobes, but how or what can I measure BEFORE I purchase a cam to determine whether I need a small base circle or not?

I do know that I'm running Eagle sir rods with the 12 point bolts that have some clearancing on them already, and additional clearancing was done on the bottom of a couple of cylinders and oil pan rail for the original build. So I was really hoping any additional clearancing wouldn't be needed...but you got me thinking now.

 

I just put together a 383 with an XR282HR, not much different from your 400 with an XR288HR. With stock 5.7 rods I had solid hits on several cam lobes. I don't know how much more clearance than stock your SIR rods will have. I put a set of H beams in and had lots of clearance.

 

Perhaps call comp and ask to see how much it would cost to have it ground on a small base, just in case.

 

You nailed it. There's no way I want to grind on the rods and possibly unbalance the thing. I already put in a "cam recomendation form" with them, plus I'll call around. Silly me.....I thought this would be easy!