New heads

[WILMASBOYL78]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ban617</div><div class="ubbcode-body">Since they are semi open won't the compression ratio be lower ? </div></div>

The #290 head was a closed chamber head that the factory added a little 'breathing room' to. It was used on the 396/350hp and 454/360hp big block applications in 1970. It was identical to the #063 used in 1969 except for the newer 'peanut spark plugs'.In both cases the advertised chamber volume [101cc] is the same in these heads and even #215 which came before that. These heads were all designed to work with a small dome piston that produced a 10.25 to 1 compression ratio.

As was mentioned, they are a great platform for a street build...with a little work these oval ports, combined with other properly selected pieces can really make good power.

-wilma

[HawkX66]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: WILMASBOYL78</div><div class="ubbcode-body">Great advice from Eric...those 290's are a semi-open chamber design and with a little work, they will help make some decent power. As he mentioned, that is a lot of cam for a baby rat...I would consider something else if you can.

I don't understand the compression calculation?? if you are using 396/350hp pistons and the closed chamber heads, the factory ratio would have been 10.25 to 1. How do you get down to the 8's [img]<<GRAEMLIN_URL>>/dunno.gif[/img]

Check with Eric on a cam recommendation and make sure you have the compression ratio figured correctly.

-wilma </div></div>I hear you guys on the cam. I contacted Comp Cams when I bought it, and it's what they suggested. Lunati suggested something similar, but solid lifter. I'm not using my L34 motor. She's bagged and stored in the corner. The 402 +.030 (408) short block I'm using has Silvolite 1445 pistons at -8cc. They're in the second picture. I'd swap out the pistons for some more like the originals, but I'll eventually build a bigger cube engine I'm sure. This should be fine for a while to keep a grin on my face.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: WILMASBOYL78</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ban617</div><div class="ubbcode-body">Since they are semi open won't the compression ratio be lower ? </div></div>

The #290 head was a closed chamber head that the factory added a little 'breathing room' to. It was used on the 396/350hp and 454/360hp big block applications in 1970. It was identical to the #063 used in 1969 except for the newer 'peanut spark plugs'.In both cases the advertised chamber volume [101cc] is the same in these heads and even #215 which came before that. These heads were all designed to work with a small dome piston that produced a 10.25 to 1 compression ratio.

As was mentioned, they are a great platform for a street build...with a little work these oval ports, combined with other properly selected pieces can really make good power.

-wilma</div></div>
These heads were also used in 69 at least on the &quot;C&quot; prefix motors which started ~July. My born with motor is a &quot;C JF&quot; coded or 350hp 396 4 speed built 7/28/69. The heads are original to that motor.
I did a lot of reading on the 290 heads after a lot of guys told me I should use my originals. The high reviews they got for being iron convinced me to buy this set. I figured for $200 I'd be doing ok. I'm going to put 2.19 valves in and leave the 1.72 exhaust.
I just re-curved my distributor this weekend. Here's what I came up with. We'll see if 20* initial is too much...

[WILMASBOYL78]

Dave...I have always set initial in the 16-18* range and total at 36*..all in by 3,000 rpm. Each motor likes something a little different...time will tell what works best. Sounds like a fun project.

-wilma

[HawkX66]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: WILMASBOYL78</div><div class="ubbcode-body">Dave...I have always set initial in the 16-18* range and total at 36*..all in by 3,000 rpm. Each motor likes something a little different...time will tell what works best. Sounds like a fun project.

-wilma </div></div>
Thanks Wilma. We'll start there and see what happens.