GOt a 67 bbc 396 that is bored .030 over and am installing 215 casting closed cambered heads on them. thinking about installing 1.88 and 2.19 valves in them. Is this a good idea? Should i just do the intakes and leave the exausts olone? This is just going to be a street engine.Also the cam is a comp. xe 268 .510-.520 lift if that makes any differance.

Chris Corwel did the research on this, and he should reply, but I'll paraphrase, it raises peak torque by 500 rpm, and increases HP by some amount.

On a 396 with that cam, I don't think I'd bother.

I wouldn't bother on a street driven motor with a mild cam..dyno results I saw gave the motor extra HP,but moved the torque curve up 500 rpms with no gains in torque..

The person who did my heads said it is not worth the money to do it on anything on less than a 427, as the gain is not worth the cash. In other words, for not all out race, on a 396, the money would be better spent on other things.

Bill

Just a thought....You might want to do just the intakes. Those are a pretty simple/inexpensive upgrade. It's the exhausts that run into worse complications with shrouding and getting close to the waterways.

Hi Bob graemlins/waving.gif

Barista is correct. Have the 2.190's installed and leave the 1.720's alone. This combination makes for a very good flowing head. I have 063's done this way on my +500hp & tq 402.

Regards,

I had the 2.19/1.88s done on my 215 heads. They are going on a .060 over 427 with a UD 272/282 solid cam. A slightly different beast. Only thing i would recommend that if you do get them done make sure they are unshrouded properly, they will have to remove a little material from the combustion chamber. Mine came out to 104 cc when finally done.

Daniel

i went from 2.06 /1.72 valves on my 396 way back when i first got into bbc and i was running 14.40's at 99 mph with 2.56 single spinner. i changed to 2.19/1.88 valves and didnt see any improvement on my motor...of course it ran to 5000 rpms and had a 272 crane cam.....

i then changed my heads to a set of closed chambered heads to bring up my compression with 2.06/1.72 valves that was deeply sunk from to many regrinds and got me down to a 13.99@ 102 or so......changed to bigger 2.19/1.88 valves.....still no improvement.....still right at 14.00 e.t.'s............then i took the heads off and did my first port job after weeks of reading how to do it and after one weekend of racing i put the car in the garage and took the heads off and ported them and unshrouded the valves......took 40 hours of work to port them......then i put the heads back on and set everything back to were it was and that dropped me to 13.60's at about 106 mph or so....

i dont think the bigger valves help much at all...........but porting makes a big difference........just thought i would share some real world experience........

I dunno ddennis68, it might have been a combination of the two. Although without unshrouding the valves in a closed chamber situation you aren't even enabling the larger valves to breathe to their potential.

Daniel

Well im going to go ahead and do it. My machinist is going to cut the 1.88 exausts down to 1.84 ,do some unsrouding and bowl blending will see how things work out.Thanks for the advice.