Hey guys. I'm deciding on my next two mods and would like some feedback on what you think the best bang for the buck is. Thinking of upgrading carb and then heads. Current combo- '73 block w/0.030 cast replacement pistons '73 non-stage unported heads, milled 0.040 8.7:1 compression (cc'ed) SP285/300 cam (0.470" lift; 0.050=228in/242ex;110 LC) B4B 750 DP #4779 1 7/8 headers (open) THM-400 Coan 3500 10" 3.42 gears 29.5x9x15 M/T's Car weight w/driver 3131 lbs Shift at 4500 rpm (Car goes no quicker at 5000 or 5500 shift points). Been thinking of an 850 HP series Holley and then TA's Alum Stg 1 heads. Let me know what you think! Also, any opinions on cam choice when I get better heads?
A bigger carb and the new TA Stage 1 heads sounds like an excellent idea!:TU: You might not want to put much of a bigger in with that compression, especially with aluminum heads. The smaller cam should help keep up the cylinder pressure. Your cam looks to be a little 'more' than the TA 212. I think I'd jump up to the TA 413. But, I think it might also help to up the compression a bit. With 9.5 or 10:1 compression, the aluminum heads would still be very streetable (pump gas). I'm guessing that your block hasn't been decked yet. Zero decking (or even .005") the block would also help raise your compression and maximize the quench area. That would give you a more 'efficient' setup, and also minimize detonation. How quick do you run now?
Thanks for your feedback Scott, and the cam suggestion. You're right, no decking done. I will move up to forged higher compression pistons one of these days and will deck the block for max compression. It's a strip-only car. I've run a best of 12.08 at 109 mph with a 1.6x short times.
Ramin I believe the bigger carb is a good move,I also like the idea of going to the aluminum heads,they're easier to woek on and more servicable if some thing happens. It sounds like you've got a good converter with the 60' times,so another thing to try is a bit more gear and then try a bigger cam,I'd say there is some usable RPM up there around 5500. And the point that Scott made about decking the block is a good one,if you take the motor out to install the heads,it would be some easy power to pick-up,if not try to go a thinner head gasket,along with the heads you'll get more for your money. Either way,sounds like an 11 sec combo with alot of potential:TU:
And THEN And then........ if you put a single plan intake, nitrous, and fuel to support it. Low 10's are just around the corner. Just keep those 3.42's to keep those rev's down. You won't need gear, you'll have JUICE! Which is more torque than you'll need. Plus with juice you won't need that high rpm bottom end and valvetrain. Stock w/ those forged pistons and good rod bolts will do just fine. ***It's not recommended to spray that dual plane.*** ***Get a sideways spray bar on the plate.*** OR.....Keep your motor just the way it is and put a TA intake, nitrous, and a good fuel pump. You should get low 11's , high 10's out of it. It would help to pull those iron's and do some bowl work on the exhaust. I've got my old sideways 4150 style NOS plate with solenoids and 75-275 hp jets if your interested. You can also call and have your plate customized with your nitrous kit. THis set up would still be good on pump gas up to 10.0 comp w/125hp shot. You could back up to a 3.08 gear if the revs climb out of the power band without effecting your et. Don't mind me uzzled: ,, I'm just an addict! FLYIN' oN tHE JUICE!!!:stmad: :stmad: :stmad:
With that compression you are a perfect candidate for the new blower... Or better yet how about a blower AND nitrous?:laugh: Michael Tweedy xsperformance@iwon.com
It seems that you get more reaction from a low compression engine on NOS than a high compression engine on NOS. I've run guys in the mid/low 12's on motor when I was running mid/low 13's on motor and got slapped around like a screen door in a tornado. But open the bottle on both cars and I'd drive around 'em almost everytime!:laugh:
Big block Regals all the way.... Don't spray your cast pistons. Get the speed pro's if you consider this. I sprayed a set of TRW for 6 years without a tear down. 300 hp fogger system. Your cam specs indicate that this is a good exhaust manifold cam. The new TA stage1 head is a stage2 head from the exhaust stem over. The roof of the exhaust port is much higher and is turned to exit in the stage1 location. This mean this head should flow really well on the exhaust side. I you change to this head i'd change the cam to take advantage of this flow percentage. Maybe a 230/238 cam about 110 center. I'd change intakes to the SP1 to keep up with these high flow heads and your car is really very light. Our regal is much heavier for some reason. You have about the best converter going. I'd also run a 1050 dominator carb. I know is sounds big but they run great on the big buicks and are cheeper then hopped up HP series carbs. Don't take your cast pistons beyond 5500. I've cast pistons come out looking kind of egg shaped and smaller. You have got a whole lot of potential in that car. It is really fast for a mild motor.
Thanks for all the replies guys. I'd love to keep hearing more, so bring it on! David, do you think a #9375 Dominator would be overkill for my current combo before I do the heads (& cam, gears, intake)? I kind of want to do these upgrades in a phased approach and had seriously considered the Dominator in the past. More questions: -Do any of the Demon carbs come with jet extensions? -Is there a carb out there that allows easier jet changes for lazy people? -Can nitrous be competitively consistent, let's say with smaller shots of around 75-150 HP? Thanks again all.
NOS info Yes NOS is very consistant as long as you run your bottle pressure a the same psi each run within @ 50psi. On a nitrous application Barry Grant recommends the next large carb over what you would normally run. So if a 950 hp holley works best on motor go to a 1050 on nitrous. I know my 1250 HP Holley Dominator came with jet extensions. Demono No: I would say put a 950 HP holley over the Dominator on you current setup but plan for the future since the Dominator is a different intake unless you choose to run a adapter.
The Carb Shop used to (and may still) sell replacement metering blocks called "speed blocks". They allowed quick jet changes w/o removing the bowls and fit on std Holleys. I used them on my S1 race motor w/ a HP 950 carb. They worked great for me because my motor was set back to where the carb almost touched the base of the windsheild and it was tough to get that rear bowl off. Jeff Peoples
If you are looking at making only a couple of modifications at a time the next two incremental modifications would be upgrading the intake and carburetor. If you are seriously thinking about upgrading to a set of aluminum heads you will need to upgrade the cam, pistons, converter, intake, carburetor, fuel system, and possibly the chassis and suspension to take advantage of the aluminum cylinder heads potential performance gains.
