So I am going to be replacing my SR heads on my B block. It's a 500" motor. My question is will it be worth it to upgrade to -1 heads? I currently have SR heads with Harland Sharps on them. Just wanted to see if the power increase would be worth the upgrade on the heads. I want to stay with one of these due to the TTI headers I have.

Thanks

My understanding is that if your SRs are opened up to Max wedge sized ports, and they are fully ported, they will be right there with ported -1s, and not far behind the very best -1s.

I have a bad habit of saying it like it is but if you are running 10.40’s with your combo in Ohio something is wrong. Work on the combo you have and find the missing ET.

I'm watching this one because I can get some tti headers cheap but don't know which block I'm going to use yet and like Bob I want to still drive on the street

Also keep in mind that the -1's use a off set intake rocker ,some to remember when to use the -1.

I would say stay with the sr'rs and get them ported. That way you can save the expenses of new rockers. I just did a set of the sr's and got 325 cfm @ .600 out of them by opening them to Max Wedge port window, some seat work and blending, also de-shrouded the chamber some. I had trouble with them backing up around .650-.700. I am a newbie to this flowbench stuff. I put these on a fresh 505 rb with a .659 lift howards solid cam and installed it in a 1974 Dart Sport and it went 9.90's on its first two passes (air was bad too).

I like the SR's. I think they can make some real good power. Like pittsburghracer said, spend some time and money concentrating on your combo. I ran 9.90's with 915's on a 440 in my 3,000 lb Cuda. Your engine/trans/rear/suspension sounds like it could use some fine tuning, and reap some great rewards.

I like the -1s we went 9.80s unported with a stroked 383 to 438. But you have a good comb right now. I don’t think -1s will give you the best bang for the buck unless you can get them cheap. Clean up what you got and improve on what you have . I bet there is a 9 in it .

I had a set of SR M.W. port sizes that flowed 340 CFM at .70 lift, I also had a set of CNC ported 440-1 that flowed 370 CFM at .700 lift.
I dyno tested two different motors with both sets of heads, a 518 C.I. 400 block pump gas motor that had 10.78 to1 compression ratio with both sets of heads (76.0 chambers) and a 526 C.I. 440 block with 12.8 to 1 compression. The pump gas motor made 727 HP with the SR and made 775 HP with the 440-1, the headers I had didn't have big enough exhaust flanges for the 440-1 heads, they where about 3/16 narrower on the bottom lip of the flange than the exhaust ports where The 526 motor made 775 HP with the SR and 845 HP with the 440-1 missing on both sets of heads worse than the smaller motor did above 5200 RPM
Both motors would start to miss around 5200 RPM, the pump gas motor didn't miss as bad as the bigger motor did It wouldn't surprise me that miss made both motors loose HP above 5200 RPM, maybe 10 to 20 HP
My message is more air flow and fuel equals more power
Are your TTI headers for the 440-1 heads, if not they need to be

Cab's numbers are what I saw between my heads and a friends SRs. Both motors were jesel equipped, similar builds. The Hp difference in full ported form is about 50 hp. If you go with -1s, after the trouble I had with Jesel intake rockers breaking needle bearing cages, I would try Harland sharp. In the end, if you think it is worth .2+ in the 1/4, go for it. That is about what you should gain.

I wouldn't change from SR heads to -1 head just to pick up a little bit of power unless it was a fully sorted out race setup and you had tried everything with the SR heads. How much power does the engine make now and how much do you want to make? My 514 makes around 900 hp with EZ heads so I seriously doubt that the SR heads are holding you back.

Nicely reworked SR’s are pretty good heads for a 500” motor.

Decided to dig up some older Indy heads stuff you posted that's still available on the Tech Archive here: LINK

How do the -1's compare to the EZ1 heads? I am also considering a change this winter.

I mentioned earlier that the difference in ALL OUT builds is roughly 50 hp between SRs and -1s. Have you considered going to B1s? That would cost more $$$ for sure, and other changes to match the rpm range and pistons, but if you are continuely thinking of making more power, it might make sense. In my case i should have gone this route as i look back. I eventually went to a Mega block, but other racers have successfully run B1s on 400 blocks.

I guess the conversation really should have started more like:

“How much faster are you really trying to go”?

Then, let the answer to that question dictate the direction to proceed.

One of my customers recently went 9.86 with his(not legal for 9’s) street/strip 3500lb race weight 69 Dart with a 505 running mildly reworked MW sized EZ heads and a .645 lift roller cam.

All of these threads would work better if the OP clearly stated their goals and budgets up front!