Hello, Im going to be building a 455 for my GS this spring. Is it worth buying 73 Stage 1 heads and have them worked on, or should i buy aluminum/ or 70 stage 1 heads? What is the difference between the flow of a 70 and 73 and would it cost the same as aluminum by the time they are worked on? Thanks.
If you do the work yourself (easy, just time consuming) and save hundreds basically 1/2 the money then stock is the game, aluminum will cost $2300 out of the box new, with no extra work.
If your going to be porting them I see no benifit in buying stage 1 heads if you do not have them already as the regular 455 heads are so close in performance up to 5000 rpm even with there smaller valves! But I gotta say here that heads for a 455 cid motor with only 2.00 and 1.625" valves is criminal!! Porting the standard heads and stuffing in the stage I size valves would be my pick as long as your not building the motor for race usage only. Stepping up to the stage I 2.13" Intake valve means that the Throat in the bowl can go up in size by 6.5% as can most of the rest of the runner area. Exh wise stepping up to the 1.755" valve will allow a 8% increase in port area which will greatly help in getting the Exh ports short turn into a much better form for high lift flow if you know how to take advantage of this! Keep in mind we are taking about doing porting work here and not just spending 15 minutes on each port with aDremel tool and a small grinding stone!
Out of the box aluminum heads will out flow most if not all of the best ported iron heads. Porting iron heads is time consuming and the cost is substantial unless you can do it yourself. Aluminum heads with entry level porting can easily flow over 300 cfm on the intake side.
I guess the first two questions that need to be asked are 1) how much hp are you looking for and (2) how much are you willing to possibly pay and deal with for fuel to get to that hp number? If your looking for more than 550 hp then unless you turn up a stage II head with its much higher level of air flow and special header needs , then aftermarket heads would be the way to go!
I do know if you need additional help with this decision but I run 72 stage 1 iron heads (same as 73s) with a mild port work, no where near full port job that Geisler might perform. I just milled the heads 16 thousands reduced the combustion chamber to 68cc's and did a pocket port and cleaned up the runner and port matched the SP1 intake. With 10.25:1 compression ratio my 3850 LB Regal ran 11.17 @124 mph which equals to about 525HP. In 2017 I upped compression to 12.25:1 and did a bit more port work, still less than major port job, everything else the same except running E85 and ran 10.50 @ 127 MPH. The camshaft is critical to get the most out of the iron heads. I run a Schneider 295-306H .520 lift running solid lifters @ .005 lash.
Even after performing some weight reduction last year by gutting the doors, installing a new light weigh rear cross member and adding aluminum calipers it still weighs in at 3680 (no driver), since the frame on the G-body Regals are known for their weakness I have reinforced it in every possible way. I have a Ford 9" Lincoln rear end with a nodular iron third member and a front mounted girdle I had to install due to bent axles housings. The engine has a girdle as well, adding 45lbs. All that reinforcing adds up. I just ordered Aluminum heads from JW and that is what he said when I told him what my ET and MPH have been. I have worked with this setup for 5 or 6 years with extensive chassis adjustments including changing the instant center and anti-squat configurations. This brought my 60 foot times down from 1.50s to 1.41 regularly with a 1.38 best. New Strange single adjustable front and back got us into the 1.30s. It feels great on launch!
you running one of the serpentine belt setups on there? Working well? Still haven't gotten to mine yet. But it Is on the "list". pretty nice 60' numbers. Especially for a Buick, haha.
Yes, I have the serpentine belt system I built way back, it still works very well. I have made several changes to gain weight reduction and open the front of the engine up compartment up for servicing the engine. As needs arises, it has become a work in progress, always looking for something new. When I get the Iron Regal out of moth balls maybe I will post a picture of the current configuration, it looks pretty good, that is, in my humble opinion. When this thing went into the 1.30's it took me by surprise, that's for sure. I had been knocking on the door for about a month running 1.41 to 1.45 pretty consistently, then at 10.30 am at Mid-Michigan Motor-Plex I was 3rd or 4th down on a freshly prepped track and it went 1.382, that felt good!
