Thread: A solid roller in a '70 400 small block???

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Here is a good link on cam basics.......http://www.popularhotrodding.com/tec...selection.html ....This is link directly to the section on LCA ......There is more to it than a straight forward X=Y type caulculation,meaning just the static compression ratio is not enuff.....The heads /roller rockers at 1.6 and intake valve sizing ,vehichle weight,etc all come into play for cam sizing.
He has 1.6 rockers ,meaning the actual engine duration is larger than the advertised cam duration,also the LCA has alot to do with it too, ,meaning a cam with alot less than 250 can be used in this situation.
Erik has folowed along with this entire build ,which goes many posts deeper than this one,he knows which heads ,what works been done to them,vehichle type ,tire size ,gear ratio,weight and intended usage and specific internal parts that are not listed in this post.
I would not be soo quick to wheel out a parts suggestion,when its someone elses money and fun at stake,unless I was 100 percent shure it was exactly what was needed ,not something that will work,especially when someone else has already given good information.

how about picking a cam for me!! 302 chevy 12:5-1 pop up's 2.02 1.6 valves camel hump's <dont give me no crap > valve springs are good up to .600 lift gonna have an 830 or larger carb on it with a tall single plane. i have a list but was wondering what some of you guys would pick

I have had a 400 small block with the short 5.56 rods for 40000 miles in a Cobra,with a solid flat tappet ,254 @0.50, 5.75 lift with 1.6 roller rockers .I ahve revved the sh#t out of it all the way to 7500rpm, often ,always, and it has never broken.The short rods are not ideal, and I have recently rebuilt with 3.750 steel crank and 6" h beam rods. The stock cast parts are very strong actually.

Hey Gassersrule, That carb is toooo big for a 302! My cam is an ISKY Z35 grind on a small base with 1.6 rockers,makes great power,but a little lumpy under 2000 rpm. I use an 800 spreadbore double pumper on a 406 that pulls 8000rpm.If you use stock 1.5 rockers this cam will be very streetable.

750 wasnt big enough ! yes see, i need that big of lift on 1.5 ratio rockers

Originally Posted by shawnlee28

Here is a good link on cam basics.......http://www.popularhotrodding.com/tec...selection.html ....This is link directly to the section on LCA ......There is more to it than a straight forward X=Y type caulculation,meaning just the static compression ratio is not enuff.....The heads /roller rockers at 1.6 and intake valve sizing ,vehichle weight,etc all come into play for cam sizing.
He has 1.6 rockers ,meaning the actual engine duration is larger than the advertised cam duration,also the LCA has alot to do with it too, ,meaning a cam with alot less than 250 can be used in this situation.
Erik has folowed along with this entire build ,which goes many posts deeper than this one,he knows which heads ,what works been done to them,vehichle type ,tire size ,gear ratio,weight and intended usage and specific internal parts that are not listed in this post.
I would not be soo quick to wheel out a parts suggestion,when its someone elses money and fun at stake,unless I was 100 percent shure it was exactly what was needed ,not something that will work,especially when someone else has already given good information.

Shawn thanks for the post. Your right there was not enough info in the initial post to pick the perfect cam given all the variables that have to be taken in to consideration to do that.

The Popularhotrodding cam theory supports everything I posted.

However I have built several 400 SBCs and the one Bill described is very similar to the engine that's currently in my 55 Belair. I did extensive research to come up with a combination that had a very broad torque curve and Max. H/P yet runs on pump gas. Initially I had a flat tappet that was .536 252 .542 260 and a old edelbrock torquer. With that setup I made 420 RWH. I then installed a roller cam with similar specs and a victor jr. That combo netted 465 RWH on 93 pump gas.A 1.6 rocker only adds about 3* of duration to that set up. So as you can see i am not just throwing random suggestions out there.
My post was based on fact not theory.

I can see by the number of post that you and Eric have that you spend a lot of time on this forum. So I can see why you would defend him with out hesitation. I can assure you I am not new to the world of cars or forums.

I have over 30 years of Hotroding behind me not including the time I spent In the garage and at the track with my dad. I have belonged to the oldest and most respected car clubs in Michigan for over 25 years.

I call it like I see it and I think all my post were correct and reactionary to what was posted by Eric .

Originally Posted by billlsbird

.....although my engine was blueprinted & balanced & built by a professional, it is built with cast parts; stock cast crank, stock 5.56 stock rods {but all ARP bolts, studs & forged pistons}. This is why I don't want to spin it to high. I think it would blow up with cast parts, wouldn't it? Plus it's a street car & I feel a 3000 true stall {3000 RPM is where it quits gaining RPM's when I punch it with the Trans Brake on} is already pushing the edge of 'street-able' for cruising around. 30" tall rear tires, 4:11 rear end with a Turbo 400 Trans & I'm at around 3000 RPM @ 65 MPH....
The only reason I want to go with a Solid roller is I heard they sound better than Hydraulics!!! {you know, the sound 'bling' thing ... Is this true??? If not, I'll go with the Hyd. roller.... THANKS Bill

Side Draft Deuce,
he has "cast parts" cast crank,cast 5.565 rods.
Are you still going to stick with your recommendation of running a cam that has 250 or more degree's of duration at .050?