I just bought a '66 Biscayne that had a 350, TH400 and a 4.10 Richmond Posi rear. I sold the 350 right away and bought a 454 out of a '73 truck. It is a '73 LS4 with 049 heads and is currently pretty much stock. I am restoring it as a period style street race car. I am doing everything as it would have been but I want a badass engine. I am thinking about going with the stroker 496 route with a monster cam but I want it to all work together. It would be a street strip car so that has to be considered as well. The heads have to stay iron as well as a stock style intake and factory valve covers. Headers will be the only thing that would make it look custom under the hood.
By the way there is nothing wrong with the '049 heads. You can clean them up yourself with head porting tools or have a head shop remanufacture them for you (either way you will need hardened seats and bigger valves which requires a five angle with back cut valve job).
I suggest you take your '049 castings and have a set of Manley 2.25"/1.88" valves installed. I would have your machinist blend the short side radius and clean up the bowls on the intake and exhaust ports, removed the rocker stud bulges on the exhaust side, and generally clean up the ports, after matching the ports to the intake gasket. You can also polish the combustion chambers but getting them coated with a heat blanket would be better.
My definition of a period street race car is 4.56 gears, rectangle port heads, factory aluminum intake and L-88 cam. You'd have to limit compression to around 10:1 for pump gas and run no less than a 4000 stall converter. It will foul spark plugs and get terrible gas mileage and have a killer sounding idle. With the L-88 cam you can run factory style rocker arms which will fit under stock valve covers. You might also consider saving time and money by boring the block .100" for 477 cubic inches with the stock crankshaft, instead of a 496 stroker.
I recently built a 496 with 049 heads. My CR is 9.75:1 & all forged bottom end. My heads were worked with 2.19/1.88 valves. Heads were ported and polished. I decided to go full roller and went with a mild camshaft.
In the photos below, you'll see how far the intakes were opened on the heads. I have a photo with a rectangle gasket and one with an oval gasket.
Good information over at Team Chevelle as suggested. Most will recommend race applications.
Will dyno in a few months at the rear wheel, but numbers show 595hp w/ 620tq. Just remember that behind an engine like this, you'll need a tranny to hold it all. I've got a 4L80e behind this engine w/ 3.73's.
Sounds like a good strong build. The only thing I'd be concerned about will the detonation. You'll have to get that timing either just right or mix a little fuel with the iron heads. Depending on your camshaft, that carburetor may be a little small if you're planning on racing. I think an 830-850 would suit the build a little better.
Please note that this is only my opinion.
Sounds like you're getting it ready for some heavy running. Looks like mostly Strip vs. Street. The 4.10's and TH400 will turn some RPM's. But if Strip use, you'll have a monster on your hands. If that's the reason for the build, again the carb is a little small if no modifications have been done.
All of the street racers I knew back in the glory days where running either tunnel rams or the stealthier cross ram that allowed you to close a flat hood. Stroker engines where welded up forged steel cranks so they were very rare. Everybody had a 427 or 454 bored 60 to 100 over and all of the cams where flat tappet solids not hydraulics. But back then we had race gas at every gas station with premium running 101 octane and Sunoco 260 blue running 106 at the pump for those who had 12.5 slugs in their motor so you will have to make some changes. The only people who had an automatic back in the days before everybody selling high stall converters where running a 9 inch converter out of a Vega's TH200 in their TH400 tranny, so just about every one had a four speed and knew there way around a gear shifter.
A period piece should have a four speed with a Mr Gasket in-line or a Hurst Ram Rod shifter a set of 5.12 to 4.88 gears in the 12 bolt rear and Hooker Competition Plus equal length big tube headers with a two four set up on a tunnel ram and a four lobe distributor running dual points. A Coors beer can was the only way to go on the east coast for an over heat catch can and the other side of the radiator had a cool can that leaked water on the strip (which is why they were banned). Of course the west coast boys all had a Budweiser beer can for their radiator over flow tank. Gabriel air shocks in the back and home made solid steel ladder bars for suspension, with an L60-15LT tire in the back on an 8 inch wide mag wheels and a set of Continental rubber 5.60-15 VW tires on a 4x15 mags up front. Glass packs where the norm for mufflers without any tail pipes as they bolted onto the collector and rattled your brain. A pioneer 8 track stereo tape deck under the dash, and a Sun Tack 10 grand tach on top. In the dash or under it where your three SW gauges for Amps, Oil and Temp. A flash light was required as well and a trunk full of GlobeMaster hand tools from the local Five and Dime. No duct tape as we used bailing wire to fix the pieces that fell off.