Thread: 385 fast burn crate engine 350ci

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Originally Posted by junior2

ok valve springs would have to be replaced. the valve springs on the fast burn are the p/n 12551483 = 1.32". if i went with the biger cam p/n 12370847 i would need 1.250" Diameter but i tried to find the spring part number and i cant. can some one help me figure out what springs i need with this cam. i think this is all i need if i were to go to the biger cam 234/230 duration and 539/558 lift.

Call Scoggin-Dickey Chevrolet.

has anyone heared of a 4/7 swap on the cam?

Originally Posted by junior2

has anyone heared of a 4/7 swap on the cam?

I know of a few running. Not always better for power but never a loss of power. Most say it's a lot smoother running. When I change to hydraulic roller in my 420cid Camaro, I will use a custom one.

thanks DennyW. im all confused ithought i had my application set for my engine. but noe its seems i have to do some mods on the heads to be able to use the 234/242 duration and the 539/558 lift with the 1.6 rockers puting me at 595 or lift??? i dont want to do this to my heads but i do want that 465hp 430tq.

unless i do the 4/7 swap on the cam with the 1.5 rockers and same springs i currently have on the 385 this should give me about what 20 hp or so .
ok lets say i do put the 539/558 lift with the 1.5 rockers will i still be at 465hp
and 410tq with out the 1.6 rockers ????

Originally Posted by junior2

has anyone heared of a 4/7 swap on the cam?

I am currently running the 4/7 swap cam. Smoothest engine I have ever run to 7000 rpm. I accelerate at 1/4 throttle just for the fun of it and shift at 5-6000 rpm. What a hoot. This engine seems to have endless happiness for revs.

Hehehe, here is something I have been considering for a while,... taking my ride to a performance shop and telling them to change the f’in spark plugs. Haaaaha.

unless i do the 4/7 swap on the cam with the 1.5 rockers and same springs i currently have on the 385 this should give me about what 20 hp or so.

I have no idea where you're going with this line of thought.

ok lets say i do put the 539/558 lift with the 1.5 rockers will i still be at 465hp and 410tq with out the 1.6 rockers ????

No. With that cam, you're over max lift for your heads even with the 1.5 rockers. Max lift is 0.525. Anything over that needs new springs and valve-to-piston clearance check.

Junior, you're overthinking the problem. Here are the options in a nutshell:

Stock cam: You can put 1.6 rockers on the intake, but not the exhaust. Minor HP gain.

Hot Cam: You can put 1.6 rockers on the intake and exhaust. That turns it into a ZZ430 clone. About 40-45 HP gain over stock.

12370847 Cam: Will not work on stock heads. About 80 HP gain over stock.

I think the biggest cam is too radical for the street, and you're putting way too much emphasis on the lumpy idle.

Originally Posted by DennyW

You can only put 5lbs in a 5lb bag, unless you expand the bag.

Aren't those bags called "GLAD"?

Originally Posted by DennyW

Your thinking the Hefty bags. The one they drive the semi into.

I haven't seen that commercial, but up here in this one commercial, the movers drop a piano and so they pack a broken grand piano into the bag and carry it up a flight of stairs, and the bag doesn't break!
So is there such a cam manufacturer named, Glad Cams? I can just see their slogan, "always gets you to the curb"

Funny bag stories.


Junior, again, a custom cam co. can build what you want and it will match everything on your car and your plans with the car. They can set you up with the correct, matching everything to take all the hassle out of it.

Originally Posted by Henry Rifle

I have no idea where you're going with this line of thought.
No. With that cam, you're over max lift for your heads even with the 1.5 rockers. Max lift is 0.525. Anything over that needs new springs and valve-to-piston clearance check.

Junior, you're overthinking the problem. Here are the options in a nutshell:

Stock cam: You can put 1.6 rockers on the intake, but not the exhaust. Minor HP gain.

Hot Cam: You can put 1.6 rockers on the intake and exhaust. That turns it into a ZZ430 clone. About 40-45 HP gain over stock.

12370847 Cam: Will not work on stock heads. About 80 HP gain over stock.

I think the biggest cam is too radical for the street, and you're putting way too much emphasis on the lumpy idle.

12370847 Cam: Will not work on stock heads? this cam will work of course
with a new set of springs. im not trying to contradict what your saying henry.
your right on the stock cam and the hot cam i can only go to 525 lift with the 1.6 rockers.that being said its doesnt mean the fast burn heads cant take over the .525 lift. because it can with a new set of springs and some grinding on the heads to clear according to Scoggin Dickey. the ZZ465HP they are selling has this cam and fast burn heads on it. the only thing that they did to the heads was grind the heads to fit a Valve Springs 1.250" Diameter with the Rocker Arms 1.6:1 Ratio, Roller Rockers. my question is once this is done to the heads on the i asume the valve quides. will i be able to down grade down the road if i were wanting to put a hot cam and the 1.6 rockers????. i am in anyway saying that i know more than you guys cause i dont. so hope noone is getting offended i have no intentions of doing so.
just would like some advice and right quidence by the pros

Originally Posted by junior2

12370847 Cam: Will not work on stock heads? this cam will work of course
with a new set of springs. im not trying to contradict what your saying henry.
your right on the stock cam and the hot cam i can only go to 525 lift with the 1.6 rockers.that being said its doesnt mean the fast burn heads cant take over the .525 lift. because it can with a new set of springs and some grinding on the heads to clear according to Scoggin Dickey. the ZZ465HP they are selling has this cam and fast burn heads on it. the only thing that they did to the heads was grind the heads to fit a Valve Springs 1.250" Diameter with the Rocker Arms 1.6:1 Ratio, Roller Rockers. my question is once this is done to the heads on the i asume the valve quides. will i be able to down grade down the road if i were wanting to put a hot cam and the 1.6 rockers????. i am in anyway saying that i know more than you guys cause i dont. so hope noone is getting offended i have no intentions of doing so.
just would like some advice and right quidence by the pros

You could always sell your heads and go Dart,AFR,Brodix etc.

i want to stick with gm parts. i just want to get the most hp out of it if i can.
but i want to stay under 500hp. i just want some one to understand what im
planning on doing so that if something doesnt seem like its going to clear that they would warn me,and advice me to do diffrent. i know im hard headed too.

12370847 Cam: Will not work on stock heads? this cam will work of course with a new set of springs.

What I posted is correct. If you replace the springs, they aren't stock heads.

will i be able to down grade down the road if i were wanting to put a hot cam and the 1.6 rockers

Of course.

Originally Posted by junior2

i want to stick with gm parts. i just want to get the most hp out of it if i can.
but i want to stay under 500hp. i just want some one to understand what im
planning on doing so that if something doesnt seem like its going to clear that they would warn me,and advice me to do diffrent. i know im hard headed too.

Can you make 450 hp with the GM heads sure can.
After a certain point and time and everyone has their own opinions on this it becomes much easier with aftermarket heads to build hp.
For my customers that number is in the 450 area.
With the cams you are looking at I doubt you will find hp by doing the 4-7 swap.
We have found hp gains doind the 4-7 swap when the cam duration is above 250 or more or at .050.
Keep in mind these where also full on race engines.