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I have a 455 with C heads that I just picked up. It currently has an unknown cam that was referred to by the PO as an "RV cam". The block was bored to .030 over and has a set of +40.3cc soup bowl pistons. The deck is at factory height and the heads appear uncut and have a fresh valve job. It has the nodular crank that was turned .010 and the rods have been reworked. I also have an Edelbrock Torker intake for it.
It will be going into a 1972 Supreme and paired with a freshly rebuilt TH350 (all new seals, 5 intermediate clutch pack, hardened sprag, etc) and a 3.42 rear end. I want to be around 375-400HP and 500ft lbs of torque. I am thinking I would like to be around 9.75:1 (maybe close to 10:1 if it will still run on 93). I will be cc-ing the heads this week so I know EXACTLY where I am at to this point.
Here is what I am looking for suggestions on:
Piston?
Cam? (I want it to behave on the street, but have "an edge" to it)
Keep the Torker intake or go with the performer?
I have a 455 with C heads that I just picked up. ...
Cam? (I want it to behave on the street, but have "an edge" to it)
Keep the Torker intake or go with the performer?
Unless you are planning to bullet proof the valve train and do lots of high RPM, I'd suggest the performer. Get a matching cam that has max power through 5500 rpm and no more than a 750 or 780 CFM carb or FI if you've got the $$$$$.
I went with the Wiseco Pro Tru piston +15.0cc and a set of Speedmaster H-beams. I figured getting the old rods separated from the current pistons and reworked for a floating pin...might as well just get new rods. Sent the rotating assembly out to be balanced.
OK. Got everything balanced and ready to start assembly. So I calculated the compression at 9.87:1 and based on the TQ40 specs the dynamic compression will be 7.45:1 based on the intake hitting the seat at 72 deg ABDC. Should I advance this cam to get a bit more cylinder pressure? I will be running the car on 93. If so, where is the line where I would be flirting with detonation? This will be a street car so losing some on the high end is not a big concern.
I'm about to start assembling this week. This is what I am working with:
455 F Block bored 0.030" over
Nodular crank
Speedway H-beam rods (stock length)
Wiseco pistons +15.0cc (0.010 below deck)
C heads- AIR bum removed,lightly ported with some bowl work
Compression ratio calculated at 9.91:1
Erson TQ40 cam (220/228@.050 110cl)
Edelbrock Torker (may switch for a dual plane later, but am going to see what I get with this one since I have it)
Headers (still need to purchase)
Carb (undecided.I have access to quite a few through a friend and will test quite a few before I make this decision)
Will be paired with a TH350 with a 2400 stall convertor and 3.42 limited slip rear.
I hope to have it on the dyno sometime in March to try out different carbs and possibly even a dual plane if I can get my hands on one for testing purposes. Any guesses to the numbers this combo will put up?
Looking for suggestions on a carb. The Quick Fuel 830 and 850 have already been suggested as possibilities. What carbs for this combo have you had success with? I have a rebuilt Quadrajet (17054937 with 70 jets, 48B Primiary rods, and a T hanger). This is all I know about this one as I picked it up freshly rebuilt. I have a friend who will be lending me a couple of Holleys to test on the dyno. ( Not sure of the models at this point).
The weakness of the Quadrajets are part throttle resonsiveness, when you are just on the primaries. It's kind of sluggish until the secondaries open. The advantage is good gas mileage. Considering how you built the motor, a square bore seems more appropriate. Although it's easy to change your mind with the carb after you install it.
QF830 Would be the best choice for your combination.
But bring some jets and air bleeds with you to the Dyno so you can really make it that much better.
She sits patiently waiting for dyno time.
Just found out that my dyno connection does not have the plates to mount up the Olds engines...only Chevy and Ford. Anyone have any leads on where in NC I could get this done?
If it’s a 902 then your engine gets mounted to a cart and wheeled into the dyno room. The housing on the dyno should have multiple holes drilled in it for various brands of engines. If not It’ll still work, but you’ll have to drill the rest of the holes yourselves as the bottom holes and dowels are the same on all GM engines. Use those as a guide then drill the rest.
Last edited by cutlassefi; Apr 11, 2019 at 05:39 AM.
Sure seems odd that the dyno guy couldn't dyno a Olds since they are the same as the other GM's except Chevy....Is everything except Fords and Chevys so odd these days? How about Mopars? Maybe this guy aint the guy you want?? Good work on your engine!!
The guy dynos a lot of engines for late models here in NC as well as some Nascar stuff. A friend of mine uses him to dyno all the drag car and tractor pull engines he builds. I don't know him personally, but from what I understand, he knows what he is doing. We are working to figure this out. Worst case scenario, I have access to a run stand for breaking in, tuning, and leak checks. I was just hoping to get a HP and torque output reading as well.
The guy dynos a lot of engines for late models here in NC as well as some Nascar stuff. A friend of mine uses him to dyno all the drag car and tractor pull engines he builds. I don't know him personally, but from what I understand, he knows what he is doing. We are working to figure this out. Worst case scenario, I have access to a run stand for breaking in, tuning, and leak checks. I was just hoping to get a HP and torque output reading as well.
Theres no way way you can “Tune” it on a run in stand. Push for the dyno, that’s the right way to do it.
I agree with Mark on the dyno to tune it precisely and correctly. It’s not necessary but it makes life so much easier and you can see the cause and effect results from changing parts and fine tuning other things. If not your essentially just firing it up in a car and tuning as you go with no numbers to see unless you use a chassis dyno. Nothing wrong either as I didn’t use my first dyno until many years into the hobby and many olds engine builds later.
Ran into a smoking deal on a carb! A Holley Ultra Double Pumper Carburetors 0-76750BL for $399...new in the box!
750CFM, electric choke, mechanical secondaries. Should be arriving today!
The weakness of the Quadrajets are part throttle resonsiveness, when you are just on the primaries. It's kind of sluggish until the secondaries open. The advantage is good gas mileage. Considering how you built the motor, a square bore seems more appropriate. Although it's easy to change your mind with the carb after you install it.
The Q-Jet is a excellent carb, once they are rebuilt and calibrated correctly if you have a good Q-Jet, save your money, call Cliffs Q-Jet with the carb number and detailed engine specs, and he will suggested the parts to tune it correctly
Q-Jets are excellent carbs. GM used it on millions of cars, for about 35 years, and were expected to perform without hesitation or bog. They don’t have issues when they are set up right.
The Q-Jet is a excellent carb, once they are rebuilt and calibrated correctly if you have a good Q-Jet, save your money, call Cliffs Q-Jet with the carb number and detailed engine specs, and he will suggested the parts to tune it correctly
Q-Jets are excellent carbs. GM used it on millions of cars, for about 35 years, and were expected to perform without hesitation or bog. They don’t have issues when they are set up right.
Sorry but I couldn’t disagree more. Did GM put Qjets on anything that made any real power? The answer is a resounding no. 370hp LT-1 SBC’s? No, LS6 Chevelles? No. Those all came with Holleys.
I’ve had a half dozen of these “performance tuned” Qjets on the dyno and not one, not one, was correct.
It has its limitations for sure. There are better carbs out there that will give a good balance of power and efficiency.
X2. You might want to put a bung in those now before dyno day. That way it’s there for later as well just in case. Jmo.
Already welded them in. That's why they are not on the engine in the pic. I have found someone able to dyno the engine. Just waiting for our schedules to align.
Already welded them in. That's why they are not on the engine in the pic. I have found someone able to dyno the engine. Just waiting for our schedules to align.
