A 396 with 366 heads

[MAC71]

I did a little bit of research on the engine in a 69 C20 that I just bought a few weeks ago. As per the engine stamping it is a 396 350 HP for a camaro or chevelle but the heads are from a 366. Only drove the truck one time and it seemed to have lots of torque but wonder how its going to run with those heads. Can any one tell me what to expect with the engine?
I have had a 72 C20 before with a 402 and this 396 has a lot more response even badly needing a tune up and having lots of vacuum leaks. I am thinking that the 396 may make lots of low end torque with the small port 366 heads and from what I have been reading is that the 366 heads have small combustion chambers so that may help also.

I know every one likes photos so here is one of my 396 all cleaned up with fresh paint.

[70CHEVYBB]

366 heads will be fine, they have smaller ports than the standard oval port they are great for low rpm torque. The only difference from 396 to 402 is .030 over bore. The running difference between the two is just that they are built different. I have a 396 sitting in my garage but decided to go with more cubes. Back 25 years I had a chevelle with a 396 I bored .125 over and was faster than h%#¥. I love the big block. Small chamber really makes no difference but open chamber heads do burn better. With what you are doing your combo should be great you also can not run closed chamber heads on pistons made for open chamber heads

[jocko]

Your engine compartment looks great! Concur you will be fine with 366 heads, but they are a little restrictive. Good torque - but not necessarily more than stock 396 closed chamber heads as would have come on your truck from the factory. I'd say drive what you've got as long as you're happy with the performance. Then, also, just keep an eye out for someone parting a correct year truck near you (on this board) and grab a set of rebuildable 396 heads and sit em on the shelf - it will make you feel better, even if you never install em!

[67 chevelle]

Should be a great truck engine , as mentioned the 366 had 'peanut port' heads , will make great low end toque , and run out of push around 4000-4500 rpms ,these heads were used in some 454s also , a 396 with stock oval ports like the common '3904390' stamped heads , with a little work is a monster that pulls and revs readily , and quickly to 6500 ,with the right components chevys 396/427 were excellent race motors

[MAC71]

Thank you all for the information.