Ford 1970 Ranchero Squire 429 Cobra-Jet: Engine build up

1970		Ranchero Squire
429 Cobra Jet

429 CJ Engine Build Up

I'm rebuilding the engine build up for my 429. To meet my performance goals of mid-twelve ETs at +110MPH, I need a solid 550 horsepower from the engine. (The Ranchero weighs about 3850 lbs, has a 2900 RPM stall, and a 3.50 rear gear.)

Currently my best ETs are 14.33 at 95 MPH. Disappointing! That gives me an estimated 255 RWHP and therefore about 360 engine HP. That isn't too far off from the 1970 rating of 370 HP, although that estimate was supposed to be conservative.

Short Block

The engine was rebuilt just about 20,000 miles ago so I haven't made any major changes to the short block. While the engine was out of the car I did

I also replaced the main bearings with new Federal Mogul 3/4 groove competition units and the rod bearings with Cleveite ones.

The rings are file fit Plasma Moly Speed Pro with .019 top gaps and .024 second ring gaps.

Oil Mods

This is Marc's engine - Boss 429 aluminum heads,
a 14-71 blower, and 540 cubes.

Although there are a lot of different ideas about modifications to improve oiling in 385 series blocks, for my application that is limited to occasional 6,500 most seem unnecessary.

I expected to have a CJ oil pan, but instead I found a passenger car pan. That is a slightly shallower unit so the CJ oil pump pickup was actually rubbing on the inside of the pan. I get a 9 qt front sump pan that will fit my chassis, corresponding pickup, and a Meling high volume CD style pump.

Heads

Cam

After the heads, the next biggest decision is the cam. I'm going with a custom grind Comp Cams mechanical roller.

	Advertised		@ .050		Lobe Sep.	Intake Center	Gross Lift
	In	Ex	In	Ex	Lobe Sep.	Intake Center	In	Ex
XR274R / XR280R	274	286	236	248	110	106	0.650	0.664
1970 CJ	282	296	238*	248*	115.5	109	0.515	0.515
1970 SCJ	300	300	256*	256*	114	109.5	0.500	0.500
Bogus cam	264	264	206	206	110		0.472	0.472

My cam have slightly SMALLER advertised durations than both the 70/71 CJ and SCJ cams. But the steeper ramps and higher lift will put a LOT more area under the curve.

I'll also need a new distributor gear to match the new cam, a Crane Cams steel gear: 52971-1 (.531" I.D.).

Valve Train

A few extra bucks spent here are worth the piece of mind. My idea is just to get the toughest 3/8" pushrods I can. One really big hassle will be figuring out the correct push rod length with all the variables!

I'll go with a Comp Cams true roller timing set and for rocker arms Comp Cams Pro Magnum Steel ones. I will also go with the premium valve springs since they offer slightly less load on the seat.

Intake

With CJ or ported D0VE heads the Weiand Stealth intake is the top choice, but I don't have room under my hood for the extra height. For now I'm sticking with the CJ intake. I've ported it our just a bit and blocked the heat risers.

My current Edelbrock 750 CFM is probably about as good as any inexpensive Holly or Demon. I'll wait until I decide what to do about the intake and maybe later I'll replace both.

Exhaust

Hooker Super Comps are available in 1-7/8" tubes. This should be plenty for my combo. Ground clearance is an issue, but looks OK. "Mike the Cobra" says with stock springs and 27.5" diameter tires (225-70-15) he has 6.25" of ground clearance. My front tires have a 0.5" shorter static loaded radius, so I'd expect about 5.75" of ground clearance. I can live with that. I'll just have to be careful.

FYI, I've considered and rejected a pair of FPA ceramic-coated shorties for around $560. The consensuses of what I've heard is shorties wouldn't be much better than the original, cast iron, CJ exhaust manifolds I've got now.

I'll back up the headers with a 3.5" to 3" collector reducer and a 3" to 2.5" Dr. Gas X pipe.