Hi. I need some help in choosing, camshaft, lifters and valvesprings etc. I have a buick 350-2, SO 260HP in my Skylark 1970 Engine is updated with: Pistons Badger 525 compression ratio: 10.25:1 Calulated at summit: https://www.summitracing.com/expertadviceandnews/calcsandtools/compression-calculator Bore: (diameter)3.80 / stroke:3.85 / Cylinder Head Volume:58 cc / Piston recessed 0.085 / Deck clerance; 0.060? Head Gasket: 0.040 cylinders 8 = 10.32 in compression ratio. If, I got the numbers right? My 350: # Cylinder heads ported, to match Intake gasket. # TA stage 1 intake. With a quadrajet 750 or 800 cfm # Hooker headers 1103 Full length. # Dual 2 inch exhaust. # TH350, stock # 8.2 bop rear axle 3.23 with posi. Street driven 98% of the time. So I don't want idle, that is to loppey. Absolute maximum for me, is a moderate idle. And I will change converter to approx. 2400-2600 rpm I want: To go faster 0-60 (8.2 sek) and on the 1/4 mile. (15.7 sek) A camshaft that works with: Power brakes. ACC. So, which cam, should I choose? TA 212, TA 290-94H or something else?
Are the heads ported in the bowl area near the valve seats or only at the intake gasket (port match)?
Yes , porting to the gasket does very little without bowl work. Might even have made flow into port worse. You will need actual specs of Pistons. (Dish size,compression height, how far down hole the actually sit) Gaskets are ussually.043-.045. According to information I found the badger piston is equivalent to the 340p piston. So assuming.060 down hole(no shaving of block) with the 10cc piston dish,58 cc head and .045 gasket you can expect an actual static compression of 9.2. The crower level 3 cam would probably give you best power degrees at 108(4 advanced) the TA 290 would be good after that or a custom grind from Scott Brown at buyracingparts.com. Add a 2500 convertor to trans . Recurve distributer to have 32 total mechanical advance at 2600 rpm . You don't mention anything porting of intake to match gasket which is more of a bottle neck then the head port. Probably be best to leave it alone to keep velocity hi where you gasket ported head. Expect no gains from the porting if you didn't smooth ports at valve opening. Shaving heads about .020 off heads for about a 53 cc chamber with net about 9.7. Or go .030 for about 50 cc chamber and about 10.05 . These are estimates but should be close. If you go higher in compression you can do a TA 310 cam or the 413. Or even step up to the crower level 4 cam at 10 to 1.these cams prefer a 3000 convertor or better. Make sure it's a small block rated convertor or you will give up an easy 500 rpm in convertor rating. The level 3 is still a good choice there but do as Steve and retard cam 4 degrees as dynamic compression gets too high.
I did do some grinding in that area and all the way in from intake, removing burrs and made it smoother. see pic. example.
Did you do the oiling mods to block? Get the later76-80 350 pickup screen(5/8), drill oil pickup passage to 1/2 in minimum. 9/16 would be better for higher rpm engines. Drill passages in toil pump housing to 1/2. And use a TA performance backgrooved front cam bearing. Booster plate and stock gears. No high volume oil pump needed.
Since you are changing cam and raising rpm range of engine you will need more oil . Put the white oil pressure spring in also(60 psi) so it can provide enough oil at higher rpm
You'll need a cam set to about 72* IVC for a dynamic compression of around 7.75:1 for premium pump gas on this combination. This could cover a range of camshafts which include (but are not limited to) Crower level 3 set at 2* retard TA 212 set at 2* retard TA 284-88 set at 0*/0* (straight up) Listed in order of mild to moderate. Crower level 3 will have a much smoother idle and excellent vacuum for power brakes, TA 212 will have a bit of a lope with decent vacuum, and the TA 284-88 will be about as big as you want to go and still have some vacuum for your power brakes, and will have the lopiest idle of the three cams suggested. With the gearing you have (3.23), a TH350 and a ~2500 RPM stall, I'd recommend the Crower level 3 cam installed at 2* retard (114* ICL) for a 72* IVC point, giving 7.75:1 DCR with a 10.32:1 SCR. This cam will have more torque down lower for your gearing needs, as well as nice mid-upper RPM horsepower, a smooth idle, better gas mileage, and plenty of vacuum.
I say the crower cam is good for him too ,Gary but my math on compression it closer to 9.: as the badger Pistons seem to be the equivalent of a 340p piston. Using the same summit racing calculator he did . Piston should be about .060 down hole, .045 gasket, 11 cc piston dish, 58cc head. So I say go 4 advance.
He could still use any one of the three cams suggested, just adjust the ICL to match the compression. I still recommend the Crower level 3 as the best of the three, based on the rest of his combination. :TU:
I'm confused? Buick 1970 SO stock 350 engine had: 9.0:1 compression ratio, GM specification, with stock piston 9.0:1. I measured the old recessed stock pistons, approx. 30 ml = 30 CC. 2 tablespoons, is a Swedish measurement, and each spoon, is 15 ml. Spot on! 9.0:1 before, with stock ~ 30 cc pistons and 9.2:1 after, with badger 11 cc pistons Are you telling me, that increase in compression ration, is only 0.2? Compression ratio gain is only 0.2:1, with a approx. 19 cc differance. How is that possible? The math don't ad up.
There's more to calculating the compression ratio than just the dish size on pistons. How far the pistons sit below the deck (which is a result of compression height on the piston from the wrist pin to the top of the piston), how much over book spec the deck height actually is (which can vary, based on how much was needed to be removed from the original casting to true the block up prior to assembly) which essentially means the deck height on these blocks will be all over the place, and must be measured if you want an accurate compression ratio reading. Then there's the head gasket thickness (about .043-.045 compressed thickness for a composite gasket), the head gasket bore diameter (usually considered 3.9"), and the head itself (combustion chamber sizes typically range from 55cc-58cc, depending if any work was done to them). Get the volume of all this at bottom dead center, and divide it by what you find at top dead center, and you'll have your ratio. Use the calculators found at wallaceracing.com if you haven't already.
Get your measurements and if you are having trouble sorting it out, we'll help. It can be a bit overwhelming if you're not familiar with all this stuff. As a rule, getting your dynamic compression somewhere between 7.25:1 to 7.75:1 (7.5:1 ideal) is a 'safe zone' for premium pump fuel and proper ignition timing on a Buick 350. Dynamic compression is different than static compression. The methods described above is to calculate your static compression ratio. This will not change once the engine is assembled. What does (or can) change is your dynamic compression which plays a role in how the air/fuel is moved through the engine with volumetric efficiency (VE) of the heads, scavenging (the exhaust's tendency to pull on the intake charge, increasing cylinder fill and adds to the effects of your dynamic compression), which of course results in your effective compression ratio (ECR), which is dynamic depending on engine components and varies with RPMs... Your camshaft's position on the timing gears and the cam's specs themselves will determine where your intake valve closes, referred to as the Intake Valve Closing (IVC) point, and it is here where the dynamic compression and dynamic displacement is calculated. With this considered, the dynamic compression ratio is effectively a secondary static compression ratio when stationary and the IVC point is determined. We can see then that the primary static compression ratio is merely incidental in determining the dynamic ratio, and will still play a role when cylinder fill is considered. This is where the dynamics get elusive, and 'rules of thumb' or 'best guesses' come into play without knowing every single aspect/detail of your specific combination. Having said this, it's best to play things on the safe side and err conservatively, which is why, based on other factors, the dynamic compression ratio is said to be safe within the 7.25:1 to 7.75:1 zone, but this is not absolute. DCR's of 8:1 or higher are possible on pump gas when the combustion chamber, ignition timing, and ambient engine temperature are ideal. Once you get your static compression ratio reading, we can calculate where the camshaft's Intake Centerline should be set at to achieve this goal.
That's gm's rated per blueprints. Sure at zero deck and the .020 steel shim gasket that could have been used at that time could have netted 9.0. But at .058 below deck and a replacement.043 fel pro gasket your at 8.2. That why the math is important to get correct power from a performance build of any engine. Mass production parts vary in sizes . That's why you need to measure. Stock 9.0 Pistons are 24.5 ccs in most cases. Same piston as the 8.5 up to 75
First Guess: the Badger pistons have an altered pin height--called "destroking" in the industry (for no good reason I can figure out.) The pin height will be .020 or so less than stock, which means the piston is .020 lower in the hole. There goes a bunch of compression. Cheap-junk "rebuilder" pistons are often made this way. The original engine probably had .020 steel shim gaskets, that you're replacing with .040 composite gaskets. There goes a bunch of compression. And then the OEMs were never very good about telling the truth about compression or horsepower. Both tended to be rated "at the brochure" rather than having any real basis in fact.
If I put in a 0.015 steel head gasket instead of Felpro 0.045, does it make any differance? Or is it still the same choice of camshaft? Is steel head gasket, a good sealing gasket?
Steel-shim gaskets were extremely common forty years ago. They're still available for some engine families--SBC and BBC, for example. I'm guessing they're pretty scarce for SBB and BBB. Chevrolet used steel-shim gaskets on the 11:1 compression LS-6 454. Yeah, they seal fine IF both gasket surfaces are flat, smooth, and clean. They need some kind of gasket sealer on them. It doesn't make much difference what sealer is used--any of thirty different products will work just fine. Some folks spray 'em with aluminum paint, others use CopperCoat or Indian Head shellac. I painted 'em with Permatex "Pipe sealer with Teflon". Doesn't matter, any sealer is fine.
On a fresh cut surface steel gaskets can seal well. On a used surface steel gaskets can be more difficult to seal. But the same amount of head shaving nets more compression increase . .025 thinner gasket 9.6/shave head .020 9.71 As far as cam the Crower seems the best choice. Proven to put a GS car into the 13s when set right. Since you have headers you could go ta310 or 413 but will require more convertor.and may only be a few tenths faster . the ta 113 is also decent . all would be similar in power.and like 9.7 or better compression But require higher rpm of engine.and low end may be soft with the lower 9.2 you may have. Or you can get a custom grind from Scott at buyracingparts.com which is only maybe 10-15 bucks more then a ta cam.
Picking up my old thread. Have been doing a lot of thinking about which cam to choose. Let's see if I got this right. Or Am I, as always, lost in space, and has no clue, as what I'm talking about. And got it totally wrong, Again...... My facts Buick 350 (1970) Cylinder Head Volume (cc) = 58 Piston Head Volume (cc) = 10 Gasket Thickness (in.) = 0.04 Gasket Bore (in.) = 3.860 Cylinder Bore Diameter (in.) = 3.800 Deck Clearance (in.) = 0.06 Stroke (in.) = 3.850 Which adds up to = 9.245 static compression And Rod Length (in.) = 6.387 And With Crower Level 2 @ 0.006 (advertised) IVC 58* = 7.761 in Dynamic compression. or With Crower Level 3 @ 0.006 (advertised) IVC 66* = 7.328 in Dynamic compression. or With Comp Cam 268H @ 0.006 (advertised) IVC 60* = 7.658 in Dynamic compression. Which is the best choise, should I advance 4* Crower Level 3 to 62* = 7.551 in Dynamic compression. Not. Crower cam price with lifters 440$, in Sweden. Comp cam price with lifters 305$, in Sweden. This is after shipping and taxes are included. Is Crower worth the price difference of 135$? Pros and cons? Any thoughts?
