LS-3 Based 416 "Sleeper" Into My 2000 Formula Daily-Driver

**ez2cdave** · 03-20-2011, 07:24 PM

I'm looking at dropping an LS3-based 416 ( 4.07" bore x 4.00" stroke) motor into my 2000 Formula hardtop ... Kooks SS long-tubes ... Magnaflow exhaust with cats ... 4L80E w/ Yank 3400 converter ... Strange S60 with either 3.54 or 3.74 and TrueTrac.

The camshaft will be an "offshoot" of the Lingenfelter GT-11 cam, with the specs "bumped up" to be appropriate for a 416 cid motor, since the GT-11 is basically designed for smaller displacements.

Anybody know how to "adjust" the specs to account for the increased displacement ?

CAM SPECS:
Intake Exhaust
Valve adjustment: HYD HYD
Lobe lift (inches): 0.370 0.378
Valve lift (inches): 0.629 0.643 with 1.7 rocker ratio
Valve lift (inches): 0.666 0.680 with 1.8 rocker ratio
Duration @ 0.006": 265 281
Duration @ 0.050": 215 231
Lobe Separation Angle (LSA): 118.0
Degrees of advance: 0.0
Valve timing @ 0.050" tappet lift: Opening Closing
Intake -10.5 BTDC 45.5 ABDC
Overlap angle -13.0
Exhaust 53.5 BBDC -2.5 ATDC
These specs are with cam installed at: 118.0 intake center line 118.0 exhaust center line
Recommended installation angle: 118 (intake center line angle)

I am shooting for a "sleeper" approach with a smooth, "near stock" idle and a broad, flat torque curve.

A very "nasty surprise" at a stoplight . . . LOL !

Dave

**brendan.9** · 03-20-2011, 07:37 PM

put in exhaust cutouts than when you want it will sound nasty when you want it to.

**ez2cdave** · 03-20-2011, 07:46 PM

Originally Posted by brendan.9

put in exhaust cutouts than when you want it will sound nasty when you want it to.

I'm not looking for it to "sound nasty". In fact, if I had my way, it would be only slightly louder than stock. I like to keep a "low profile" on the street to avoid unwanted attention from "Barney" ( cops in NC ) !

Louisburg, NC is near Raleigh, NC . . . Lots of "ricers" here and there was a big street-racing bust a few years ago and the cops take a very dim view of "vehicles modified for the purpose of speeding or racing" . . . Yes, I did a "double-take" at that wording too !

Dave

**silverWS6** · 03-20-2011, 08:02 PM

Magnaflow sounds pretty quiet at idle and some cats should quiet it down a bit too.

**ez2cdave** · 03-20-2011, 08:13 PM

Originally Posted by silverWS.6

Magnaflow sounds pretty quiet at idle and some cats should quiet it down a bit too.

Quiet is a good thing to me . . .

I have heard good things about Magnaflow mufflers being free-flowing and reasonably quiet. I want to avoid raspy and overly-loud mufflers, as they drive me crazy since I am older now ( almost 50 ) and attract cops like flies !

What is the quietest free-flowing muffler out there today for an F-Body? Of course, the larger displacement makes the choices more limited ( 416 vs 346 ).

25 years ago, I had a 1970 Chevelle SS454 with Hooker Super Comp headers and a dual 2.5" ( "big" back in the day ) exhaust, using Walker Super Turbo reverse-flow mufflers. They were quiet, high-flowing and "mellow", unlike the majority of the exhausts I have heard in recent years.

I am pretty that those mufflers don't fit on a 4th generation F-Body, at least not without serious ground clearance issues. I don't fancy banging my exhaust on speed bumps and dragging it in parking lot entrances !

Dave