So, I took my 326 to the dyno this week for break-in, tuning and power pulls. The motor started right up, ran very smooth, sounded great, no lifter noise or leaks, made 63 psig oil pressure until we got into the power pulls when it warmed up, even then it never fell below 49 psig. But, the power results were disappointing. First, here's the build basics:*1967 326 block, bored 0.060" over, SP cast eutectic pistons, crank ground 0.010" under, SP tri-metal bearings. Main and rod clearance were all in the 0.0017" to 0.0023" range. Piston clearance might be a little tight at ~0.001", mfr wanted 0.0015".*140 heads, intake matched and cleaned up pockets, removed burrs from runners but otherwise did not increase port size, SI SS 1.92/1.66 valves, 3-angle valve job, threaded rocker studs, Scorpion 1.5 full roller rockers, expected compression 9.3:1*Lunati Voodoo 10510701 cam, 213/219 @ 0.050", .455/.468 lift, installed at 108 ICL.*Edelbrock P4B intake w/Edelbrock 1406, 600 cfm carb*Stock dizzy with HEI kit*Melling M54DS oil pumpThey have a Holley 600 cfm carb that they use on almost every motor for the first 20 minutes to make sure it runs and the cylinders don't get gas-washed, and it ran well but A/F was in the 11's and specific fuel consumption in the mid 0.6's (.62 to .66), so it was too big for my motor. They broke in the cam for 20 minutes, then seated rings by varying speed and load, but only for ten minutes or so, before moving on to power pulls.Our first couple of power pulls the motor made 240 hp at 4,700 to 5,000 rpm and peak torque 300 to 310 ft-lbs at 3,600 rpm. Torque stayed pretty constant up through 4,500 rpm or so. We played with timing between 32 and 36 degrees full advance, then we swapped on my Eddy carb, and did no better. A/F did come down in the 12's at full throttle with my Eddy, and specific fuel consumption down into the 0.55 range, which they thought was better. The Eddy carb, for all it gets crapped on, ran fine with no low spots or bogging, they said they see a lot of them and they always run great right out of the box. Since air consumption was only in the 350 to 370 cfm range at full throttle, they thought maybe my carb was too big, so we swapped on a 500 cfm 2-bbl, and did worse. We more or less ended up with my carb and 32 degrees advance with the 240 hp and 310 ft-lbs of torque as the best we could do. I was hoping for closer to 300 hp and 350 ft-lbs. Everything I've read about other builds suggested this was about right. The guys at the machine shop with the dyno build race engines and dyno-test 3 to 10 engines a week, they were at a loss to explain it. They said the numbers all look good and the motor runs great, just not making the expected power. They did say, 'we don't do many in this small cubic inch range'. I was hoping they'd find a calibration glitch in the dyno....Couple things I forgot to do was run it down to idle, it did stall a couple times when the rpms fell below 1,600 or so early on, and I've always thought the engine was 'tight', hard to turn over by hand. Not sure how much power that would rob. The other thing we didn't do is a compression test. I'll set up on my engine stand and do this tomorrow. I have the dyno sheets, I'll try to scan a couple of them and post them early next week in case anyone who knows what the numbers mean wants to see the gory details.Was I being too optimistic about power output? I've read a few articles about 350's that put out 330 hp without too much trouble, so I figured 0.9 hp/cu. in. was not unreasonable. On the bright side, it didn't blow up, it did run smooth and mechanically quiet, it did pull strong and steady up to 5,100 rpm each time, and the day at the dyno was a blast, couple buddies came by to help and we had a post-mortem at the local pub.Any comments appreciated as usual, I'll post anything I learn in the next couple days.Scott
hi bummer,your static and dynamic compression should be decent.static might be around 9.5 at .060" i assume the heads might have been surfaced before.your cam won't have a very late closing time, maybe around 54 deg abdc.i hope you see at least 165 psi on your gauge.sorry but if you're looking for hp that cam should be in a box stock car imo. it will be snappy off the bottom but that's it.you can eek out a bit more hp sand rpm if you retard it around 4 degrees but it won't be much.i would run a comp xe262h, it is slightly larger with a 110 lsa.if they did not truly pocket port the heads you might be missing a bit there but that cam is still fairly small.if you run the 262 i suggest at least 3.00 gears, 3.23 - 3.31 are nice with a 262 - 268 cam depending in driving preference.what is your top ring gap? i think it should be around .026" with those pistons. if its less the ends might but together when hot.unless the mfg said .001" cyl clearance is ok i would not run it. .001" is 30% less than .0015. that's a lot. .001" is super tight imo. i would not have run it that hard right away. * Advertised Duration (Int/Exh): 256/262 * Duration @ .050 (Int/Exh): 213/219 * Gross Valve Lift (Int/Exh): .455/.468 * LSA/ICL: 112/108 * Valve Lash (Int/Exh): Hyd/Hyd * RPM Range: 1000-5300 * Includes: Cams Only
I don't know what I was thinking, I can't do static compression when the engine is 25F, which is my garage temp this weekend, and it'll be challenging to run it on my stand very long to warm it up. I knew the cam was mild, I didn't think this mild, power is not even up to factory 2-bbl numbers, for what they're worth. I did the port work on the heads myself, it's possible I made them worse, but I stuck pretty close to the popular tech article on the 360 Dodge that everyone references, although I did not open the runners more than 10% in volume. Top and middle ring gaps were as recommended by Sealed Power, .020" to 0.022".Looking back I made a couple big mistakes at the dyno. I should have insisted on longer break-in time, and I should have done some work at idle and off-idle. It was so far off the power mark that we were focused on big smoking guns, not small stuff.
"I don't know what I was thinking, I can't do static compression when the engine is 25F, which is my garage temp this weekend,"LOL, Hey, get a block heater.Actually you still can, they won't be terrubly different when it is warmer because the rings and cyl dimensions won't change thsat much. if they do you have WAY bigger probs.in other words if it says 130 at 25 deg f it will not be 145 after it is hot and you are screwed.xxxxx"I knew the cam was mild, I didn't think this mild, power is not even up to factory 2-bbl numbers, for what they're worth."dyno numbers can be misleading. there are a couple different styles and models and they all prodfuce different numbers to some degtree.the numbers you got are what i would expect. others might think they should be different.xxxxx"I did the port work on the heads myself, it's possible I made them worse, but I stuck pretty close to the popular tech article on the 360 Dodge that everyone references, although I did not open the runners more than 10% in volume."Well I doubt you could have hurt them either, that cam does not need much air, lol.xxxxxTop and middle ring gaps were as recommended by Sealed Power, .020" to 0.022".That's ok except that that is for a cyl that should be .0005" larger according to you which is not good however they are not too wide and providing they did not but ends and do some damage they will not leak more air thru the gap then they should.I am kinda curious as to why you set the rings to the proper spec but the piston/cyl clearance 30% less than what was recommended.xxxxxLooking back I made a couple big mistakes at the dyno. I should have insisted on longer break-in time, and I should have done some work at idle and off-idle. It was so far off the power mark that we were focused on big smoking guns, not small stuff. No comment other than to say that boring your cyls so tight might not have helped but it's hard to say.
power hone it with some deck plates. put a 220 degree cam in [like comp cams 275DEH #51-208-4] advanced an additional 4 degrees and use RHOADES high bleed down lifters, it WILL make more power!! the cam specs are....219-228 at 50, 110 degrees LSA, 0.462-0.480 lift. $129.95 at c-n-c motorsports. p.s. tri-y headers or 1.5 inch tube headers [andy's auto sport] are your FRIEND. you will LOVE a TH-2004r trans and 4.10 ring and pinion set... see ya
Shy - I didn't do the bores, I had a machine shop do 'em, I measured them after the fact. I was not so confident in my own skills and tools to take it back and have them open the holes up more, but wish I had, another lesson learned.Dond - I see your point about more cam, but I wanted a more tractable street engine, so I shied away from too much duration, especially for the 326. I still think properly assembled these components should have made more horsepower.Here's one of the dyno sheets, one of the three best runs: Might get to a compression test this weekend. I've been mulling over trying to get a measure of the torque it takes to turn the engine over with the starter as a way to measure if the engine is overly 'tight'. I could measure amps and voltage and convert (ratio of the starter/flexplate gears included), but would there be any data to compare it to? I posted a few months ago how I was concerned about how much static torque it took to get it rolling free and then rotate it by hand, like 70 ft-lbs to get it off the dime and then 25 or more to keep it moving. In the end, I'm probably going to assemble the car and drive it for a year before doing anything drastic. To bring it somewhere, have it taken apart, measured and re-clearanced would be another grand, and I hate to pour that into the 326.
hi,What is your rear gear ratio?"Dond - I see your point about more cam, but I wanted a more tractable street engine, so I shied away from too much duration, especially for the 326. I still think properly assembled these components should have made more horsepower."i run the comp xe262h cam on ford [sorry to use the "f" word] 289's and 302's all the time with 3.23 gears and it has plenty of bottom end, if i add around a 2000 rpm stall then they get off the line pretty well.i would not recommend anything much bigger for you. any cam you advance will lower the entire operating range by around 200 rpm which dond suggested earlier in the bigger cam. it would work on these also but a 326 eng is not a torque monster, it wants to rev a little.if it was too tight it would have either locked up or scored the pistons or bearings, no way to tell unless it is disassembled.from 0 - 3600 rpm you made 211hp, imo, that's decent, and what i would expect with your tiny cam.now from 3500 - 5000 you only made 28 hp!!!! WTF?between your tq and hp your dyno sheet tells me that your engine was totally completely done at 4100-4200 rpm and this would be your shift point.i might have also tested around 12.5 afr just to see.might have check timing too.what rpm did the advance reach max?as you know the rpm range on that cam says 1000 - 5300
hi, me again. please note my suggesting the use of the high bleed down lifters. these are well known for their ability to REDUCE seat to seat timing at low rpm,AND valve lift at the same time. when rpm rises the bleed down affect diminishes and full cam timing and lift are reinstated, so in effect it acts like a small cam down low, and a bigger cam with more rpm! cave man variable valve timing, with stone axe reliability! also note that i recommended advancing the cam 4 degrees more [which shifts the power peaks to lower rpms] than the cam is ground at. in totality these combine to boost net cylinder pressure which will boost torque. also note that the th-200r4 uses a 0.67 overdrive ratio. this combined with the 4.10 rear gear set is the equivalent of a 2.74 ratio. but the first gear ratio is 2.74.... so this gets the car moving easy with little throttle opening. by the way comp rates that cam from 1,500-5,800 rpm. when i did a dyno sim with a 326, it showed a 5,500 rpm horse power peak. all just food for thought. good luck to you with whatever YOU choose to do.
its christmas and im bored to death... i did a comp cams CAMQUEST6 dyno-sim for the 326...3.78" bore x 3.75" stroke, 2-valve low perf. heads, pocket porting/valves, 1.92 x 1.66, 9.3 comp. ratio, dual plane std-flow manifold, 600 cfm 4-v carb, gasoline fuel, small tube headers with mufflers, #51-208-4 hyd. flat tappet cam [which has less lift and duration than the #51-223-4 XE268H] and the cam picker said... 328 horses at 5,000 rpm, 375 LBS.FT. at 4,000 rpm. the closest thing i could find to your voodo in the comp catalog was #51-207-4 with specs of...211-221 degrees at 50, 110 LSA, 0.442-0.465 lift, the sim predicted ...318 horses at 5,000 rpm, 387 LBS.FT. at 3,500rpm. YOUR reality is disapointing, agreed. when i tried a hyd. roller which offered more lift it responded well. maybe that is key? perhaps keeping your cam and switching to 1.65 rockers could help. intake lift goes from 0.455 to 0.500", exhaust changes to 0.512". something to think about. peace
Dond - thanks for running those, I thought my motor was off the mark even with my mild cam. I have seen other similar 326 and 350 'stock' builds do close to 300 hp/350 ft-lbs, on paper anyway. I was waiting to respond to previous posts until I did a good compression test, between work and Xmas that ain't happened yet. I did talk through some details with an engine builder, I might not have the compression I was hoping for. I did plane the heads 0.010", but he says new pistons are 0.020" shorter (1.710" versus stock 1.730"?) to account for decking the block, which I didn't do. I also used the stock Best Gasket head gasket at, what, 0.049" compressed thickness? Not just compression but quench might be weak.I'm going to get to the compression test this weekend, will again post results. And, since it's winter here and we love an opportunity to get the woodstove going in the garage, light up a cigar and stick a few beers in the snow, I might pull it apart and cc the heads, etc., see what I can fix.
i THINK you should tear it down, power hone it with deck plates for a looser piston fit, AND use a much thinner head gasket set. the rocker trick might get ya some pep too. good luck bro.
This is stock Pontiac ratings 67 326 engines something must be wrong ? Year Engine HP Engine code Trans CR Cam Head BBL Carb No. Misc1967 326 250 HP WC M 9.2 254 140 1-2 7027071 Block Casting # 97863391967 326 250 HP WH M 9.2 254 140 1-2 7037071 A.I.R. Block Casting # 97863391967 326 250 HP WP M 9.2 254 140 1-2 7027071 Block Casting # 97863391967 326 250 HP WX M 9.2 254 140 1-2 7037071 A.I.R. Block Casting # 97863391967 326 250 HP XF A 9.2 254 140 1-2 7037062 A.I.R. Block Casting # 97863391967 326 250 HP XI A 9.2 254 140 1-2 7037062 A.I.R. Block Casting # 97863391967 326 250 HP YJ A 9.2 254 140 1-2 7027062 Block Casting # 97863391967 326 250 HP YN A 9.2 254 140 1-2 7027060 Block Casting # 97863391967 326 250 HP YO A 9.2 254 140 1-2 7027071 Block Casting # 97863391967 326 285 HP WK M 10.5 254 141 1-4 4243S Block Casting # 97863391967 326 285 HP WO M 10.5 254 141 1-4 4245S Block Casting # 97863391967 326 285 HP WR M 10.5 254 141 1-4 4243S Block Casting # 97863391967 326 285 HP XG A 10.5 254 141 1-4 4248S A.I.R. Block Casting # 97863391967 326 285 HP XO A 10.5 254 141 1-4 4248S A.I.R. Block Casting # 97863391967 326 285 HP XR M 10.5 254 141 1-4 4245S A.I.R. Block Casting # 97863391967 326 285 HP YM A 10.5 254 141 1-4 4246S Block Casting # 97863391967 326 285 HP YP A 10.5 254 141 1-4 4246S Block Casting # 9786339
From my previous post"What is your rear gear ratio?"xxxxxI thought my motor was off the mark even with my mild cam. I have seen other similar 326 and 350 'stock' builds do close to 300 hp/350 ft-lbs, on paper anyway. do not fall in love with dyno results. unless you are comparing the exact same specs, elevation, temp, humidity and dyno results can vary widely.i think only tuffnuff might know haw pontiac came up with their hp/tq numbers so its hard to compare to those too imo.you can not compare a 350 to a 326 pontiac.xxxxxI was waiting to respond to previous posts until I did a good compression test, I did talk through some details with an engine builder, I might not have the compression I was hoping for. I did plane the heads 0.010", but he says new pistons are 0.020" shorter (1.710" versus stock 1.730"?) to account for decking the block, which I didn't do.did the machinist or eng builder that bored your block to only .001" piston clearance NOT tell you that?xxxxxI also used the stock Best Gasket head gasket at, what, 0.049" compressed thickness? Not just compression but quench might be weak.lol, well stock deck height might be around .020 and if your pistons are .020 shorter then yeah a deck height of around .040" might be just a bit much to say the least.xxxxxI'm going to get to the compression test this weekend, will again post results. I might pull it apart and cc the heads, etc., see what I can fix. yOU CAN OBVIOUSLY MILL THE HEADS. YOU CAN GO AROUND .025" FROM STOCK before you might have intake fitment probs. you can go .040" then mill the intake to fit. you can not angle mill the heads like some say, that's bogus.even if you have 12:1 compression that cam is still girly, if you get 9.5:1 comp and use a comp XE262h cam like i suggested, you will have around 60 more hp. that will put you over 300 and it will no flatten out a 4k like yours did.I personally hate variable lifters. yes they do work as described.xxxxxYOIUR COMP - Stock comp on that eng is 9.2 but who knows, ford lies about comp. assuming that is correct you heads are 64 cc's. irregardless of the cc this is what happewned.mill heads .010"install .020" shorter pistons bore block .060" overusing all this info your static compress is exactly the same as stock thanks to milling your heads and boring your engine, so theoretically, increasing your comp by only .3:1 to get 9.5:1 will not help you a lot but i would still do it.the cam you have has more dyn comp than a stock cam too so you should see comp numbers of around 145.
MR. Gasket sells a gasket that may interest you. #5780G, summit sells them for $36.97 each. 3.87" bore diameter, 0.028" thickness, 5.397cc volume. i would think boosting your dynamic compression ratio would be in your best interest. i'll stand by my recommendation of lifters, cam and advancing it to trap more cylinder pressure. as i stated the #51-208-4 has less seat to seat timing than the #51-223-4 unit. i think the 1.65 ratio rockers will also be helpful increasing lift from 0.462" to 0.508" on the intake. i would not use them on the exhaust in this application and would keep the 1.5 rockers there with 0.480" lift. of course in the end its all up to YOU, its your car. hope this helps.
+1 on the gasketi was just looking for the same thing.your compression will go up .25:1 for a possible static comp of 9.45:1 simply by installing the gasket not to mention it also reduces your quench area by .020", very cool.if your heads are only milled .010" from orig then you can safely mill them another .013 - .015 providing your eng deck has not ben surfaced.this will increase static comp another .2:1 for a total of around 9.65:1.this all increases your dyn comp and cylinder cranking pressure too.by around since your current cam has an ivc of around 4 deg less than a stock cam, this boosts your cylinder cranking pressure by around 6 psi.this is all based on your piston to cyl height being close to .040". if you yank the heads you must measure this.if you use a thinner gasket and/or mill the heads you will need to check you valve train geometry. you might need different length push rods.basically you hope to have around 160 - 165 psi compression on your gauge with all the plugs out and the throttle propped open. this is ifdeal for a high perf eng running iron heads and 93 octane. you can run a bit more with e85 as long as it is jetted and timed properly.