Hi all, just a quick question regarding big block heads. I am currently running the Edelbrock Performer RPM package (carb, intake, and cam) on my 402. I was planning on finishing the engine off with their Performer RPM heads. Does anyone have these heads on their 396/402 that can maybe shed some light on if they are any good or should I opt for Brodix or Trick Flows? I am currently running 396 stock closed chamber oval ports from a '67 L35. Edelbrock claims with my current setup, adding their heads will net 50-75HP. Does this sound realistic? Also, I was planning on adding roller rockers, how much could I expect to gain there as well? Thanks in advance.
Question on BB heads
Nvr2Fast
21 - 36 of 36 Posts
Ed,my heads are totally stock..no porting,2.06/1.72 valves,and stock stamped rockers.
Best MPH was 103.9 and thats with no tuning.Out of the box 750 vacuum secondary Holley (other than the 2nd from lightest secondary spring) and a used $50 Accel HEI
Best MPH was 103.9 and thats with no tuning.Out of the box 750 vacuum secondary Holley (other than the 2nd from lightest secondary spring) and a used $50 Accel HEI
I know it's comparing apples to oranges, but what kind of power are you putting out of that 454? Do you think mid to upper 12s is a realistic goal with some head work and possibly changing out the vavletrain(i.e. roller cam and roller rockers)?
I'm running a 3.31 posi, but hell, for you to break into the 12s with 2.56s, you did something right...lol
I'm running a 3.31 posi, but hell, for you to break into the 12s with 2.56s, you did something right...lol
Ed,best guess using the typical formulas is about 440-450 HP at the crank..my car weighs about 4000 lbs.On a dyno,a duplicate of my motor with 2.19/1.88 valves made 490 HP/525 ft/lbs torque
Roller rockers aren't worth anything ET wise,but the proper cam will get you there.A solid cam in the 240-245ish duration @ .050 along with big valves is what it would take IMHO
Mid-high 12's with an M20/3.31's might be possible,but realistically,low 13's would probably be where its at,and you will need sticky tires too,especially with a 4 speed
The 12.99 was a best in absolute perfect condtions in regards to traction/weather.
Car was usually good for a 13.20-13.30 average with some wheelspin.
FYI,my username is confusing in regards to my current ride...the black cherry 70 is a TH400 car.
Roller rockers aren't worth anything ET wise,but the proper cam will get you there.A solid cam in the 240-245ish duration @ .050 along with big valves is what it would take IMHO
Mid-high 12's with an M20/3.31's might be possible,but realistically,low 13's would probably be where its at,and you will need sticky tires too,especially with a 4 speed
The 12.99 was a best in absolute perfect condtions in regards to traction/weather.
Car was usually good for a 13.20-13.30 average with some wheelspin.
FYI,my username is confusing in regards to my current ride...the black cherry 70 is a TH400 car.
Ed,I'm in Hamden..right outside New Haven..about and 1.5 hour ride from LI/the city
That picture was at the LVD Nostalgia Drags
That picture was at the LVD Nostalgia Drags
..if you ever need any help,give me a shout via the board or email mr.4speed@lycos.com
..the garage is always open for beers too
where is Red Hook btw?
..the garage is always open for beers too
where is Red Hook btw?
Joined
·
7,878 Posts
I just wanted to add that it`s my understanding that the bigger valves will not work with the stock style piston. Since the closed oval port motors used small valves, the pistons don`t have the reliefs for the big valves or high lift cams.
Let me say that I do not know this from experience and was told this by 2 machine shops when I was building a 396 years ago. I ended up just selling the motor due to lack of funds. I`m sure someone here can tell you one way or another if there will be clearance issues.
Let me say that I do not know this from experience and was told this by 2 machine shops when I was building a 396 years ago. I ended up just selling the motor due to lack of funds. I`m sure someone here can tell you one way or another if there will be clearance issues.
Joined
·
7,878 Posts
Anthony,they where 290 castings with 2.19/1.84 valves and mild porting.
Its fellow TCer "cmt454"
...FYI,stock 396 325 HP motor (small dome) with #063 heads and big valves..with the 2nd design L88 cam..no piston/valve issues.
...needed 4.88's
Its fellow TCer "cmt454"
...FYI,stock 396 325 HP motor (small dome) with #063 heads and big valves..with the 2nd design L88 cam..no piston/valve issues.
...needed 4.88's
Chris is correct, 290 castings with some bowl blending and some ushrouding of the valves. Nothing real involved. Peak torque was 531ft.lbs@3900 rpms. I am changing my entire combo. Brian recommended a new solid cam for me, which I have. Its a Comp XE 273/279, 236/242@.050 .570in and .580 ex. for the lift. Its ground on a 107 LSA and 107 ICL. I now have an 8" BTE 4000 stall converter and 4.10 rear gears. It should be interesting at the track next year
Joined
·
7,878 Posts
Thanks Cris. I thought your motor would be perfect for me 70 but I think I`ll upgrade to bigger valves and do a little bowl work to the heads. Also, thanks for the valve clearance tip. I was tols by the 2 machine shops around here that it would be a problem but obviously they were wrong since people are doing it without problems.
Sorry guys, I miscalculated CR on my engine after going back and re-running the numbers using the specs provided for the piston, I came up with 10.01:1, which is exactly what the guys at Summitt said as well. I kept thinking 9.5:1 seemed awfully low for a stock type replacement domed piston when the orig. CR from factory was 10.25:1. Anyway, sorry for the confusion, this has also helped me a little as far as what direction I want to go for added performance...
First though, I would like to see numbers on the Dyno and the 1320' before I make any modifications...
Thanks for all the input too...
First though, I would like to see numbers on the Dyno and the 1320' before I make any modifications...
Thanks for all the input too...
21 - 36 of 36 Posts
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
