Eagle and Apache Piston to Valve Clearance with Custom Cam

Hello All,

Just curious...Does anyone have a SWAG at how much cam lift (custom grind) could be run on an OEM Eagle and/or Apache engine if the VVT was locked and the cam run straight up?

Look at the specs on the 274VVT Comp cams, iirc they are pretty much the max with stock pistons.
http://www.highhorseperformance.com/Comp_Cams_Hemi_Phaser_274_Camshaft_p/201-428-17.htm

Excellent, thank you!

I'm curious why these Hemi cams use such a wide LSA (112-114) compared to what we use in a SBM on an oval track (105-108). And the duration numbers are lower, too. The last SBC we built for my kid's dirt car used a 248 degree @ .050 and a 106 LSA.

I realize a wide LSA gives better driveability... the last blown early Hemi I had done for a hot rod used a 113 LSA.

Does anyone build a cam without the fancy vvt stuff for use with a carb?

I would imagine guys like Mike Jones can do what I need... just wondering if any of the Gen3 only outfits build what I would need.

You can have a cam ground however you want it. The wide LSA is mainly for ease of tuning with a factory ECU from what ive seen. My cam was considered "at the edge" of what could be tuned 6-7 years ago and its 600/247/255/114 and has only a slight lope. If using a VVT short block you need a cam with the VVT front journal even if VVT is locked out. A non VVT pre-09 5.7 or any 6.1 are normal front journal cams and seem to be cheaper overall.

A superior flowing head will not need a huge duration cam to crutch it.

The wide LSA limits overlap. It also makes sense if the intake tract doesn't need as much time to fill the cylinder. Then one keeps the intake closing point where the engine wants it and use the lobe's duration to place the opening point. If the intake valve opens too soon, exhaust pressure starts flow backwards in the intake port. Also a later opening intake valve allows the piston to come closer to it at TDC, pushing the exhaust gases towards the exhaust valve.

These new engines with great airflow have to be approached differently that the oldies.

R.

EFI

Hughes sells the sames cams for magnum motors in carb version or efi version

I figured he EFI had something to do with it.

In the professional dirt late model world the wide bore, big bore, short stroke engines rule the roost. 850 HP running at 8200-8500 lap after lap. I will never have that kind of power but, where I run, 650-700 HP is the norm. My SB 383 is a mid-pack motor at best... I'm always the guy using everybody's leftovers running on a zero budget.

Whether I get to the point that I build one of these I don't know... but buying a core for a mockup motor is a good start.