airjunky

It is unofficially written in stone that people who have run the zz502 cam at bravo friendly rpms have had many enjoyable hours running sub 400lb spring rates. Nice lopey idle like the 731 cam . With carefully selected springs for what you personally are going to do with it , stock lifters (dirt cheap) will work fine.you will have to watch the initial set up , but with the type of exhaust your using , reversion can be avoided.
Still scratching my head how you have a mag block or rotating assy with flat tops . Something isnt right there and i wouldnt do anything else until you have positively identified your rotating parts

MILD THUNDER

Yea, mag engines had small domes. 310hp 7.4 engines had flat tops if i recall.

airjunky

At one point in bbc history , there was a abundance of cheap peanut port wagon and truck smog motors o'plenty. And it seemed like everybody had a top end from a grenaded ls6 or pre smog vette motor.
Everything had crappy compression , so how could it be any crappier ? The people said.
Just sticking a boat cam in a wheezer 230 horse 454 instantly brings another 100 hp to the table , so how about some real heads , a real intake and a skosh more cam ?
It just didnt work . . Everybody has forgotten . That was before the internet . People have moved on with their lives.
I would have to be standing next to a dyno where someone flips a 385 horse mag motor down to 7.8 to 1 and it still twists out 360hp then i still prob wouldnt believe it lol

airjunky

Flat tops usually came attached to 3/8 rods so if you got a forged crank and 7/16 rods with flat top pistons then thats all kinds of weird there. Ill bet you have a l29 .

MILD THUNDER

Sounds like an L-29 bottom end to me too

TylerBurich

Joe, What did the 525sc have for pistons? Could he have a set of the lesser compression forged units from one of those engines?

SB

Flat top piston is a buzzword. Came from the small block guys.
"It's got flat tops, fueler heads, and a Harley double pump." LOLlllllllll.

Anyway, I would get a cheap boroscope if you don't have one and take a look at the top of the piston. You may even be able to see a part # on it.

Here are some smart phone boroscope's for cheap:

https://www.amazon.com/borescope/s?i...Ck%3Aborescope

pjv911

The engine is apart and pics already taken. Just don't see an option to post them.
Also crankshaft is forged and so are rods. Block is also 4 bolt main

SB

Being a non paying member you have to use another site to host them.

MILD THUNDER

They had dished piston.

The L29 Engines, used a flat top piston, but had a 100cc "vortec" head, which netted around 9:1 compression . The "mag" engines, used a small dome, and were still not 9:1, because of the typical 118cc bbc chambers.