What to do with a 1970 429 for rebuild?

Mus408 · #1 (**permalink**) 04-04-2009, 10:14 AM

Rebuilding an N code 429 Thunderjet engine for high performance street,with a pump gas,93 octane,friendly compression with the iron 75 cc or possibly the Edelbrock RPM Performer heads. Anyone have any piston combos that will work for this? 9-9.5 compression with the stock 75 cc iron heads? Or 10-10.5 compression with the aluminum RPM heads?

CarsByCarl · #2 (**permalink**) 04-07-2009, 05:48 PM

When using 75cc heads:

9.25:1 will require a -20cc dish

10.25:1 will require a -10cc dish

Flat tops will give you approx 10.7:1 if left in the hole a bit, which can work with alum heads and pump gas.

There is unfortunately a very limited selection of off-the-shelf 429 pistons available if using a stock rod.

Stock cast replacements like the Silvolite 1161's have a -12cc dish
KB offers hyper flat tops
Speed Pro offers forged flat tops
Other than that, you'll need a custom

You can use 460 pistons with the 429 crank and aftermarket cadillac rods if you're willing to do a little work on the rod bushings.

You can also use a 460 crank, the rods you have and 460 pistons.