When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Theoretical and Street RacingUse this board to ask questions about street racing, discuss your street races, and "who would win?" questions. Keep it safe.
Hey there ThirdGen Nation! I was wondering if there were any helpful souls out there that would be willing to maybe run some numbers and help me put together some ballpark Hp/Tq figures on a Small Journal 327 I'm building. I am an Automotive Technician so I'm not a total idiot, but I understand sequential EFI on everyday drivers OBD2, and driveability issues not Hot Rods. This is my first real in depth build of an engine so I Definitely welcome any and all criticism/suggestions for improvement. Thanks guys. I greatly appreciate it.
Shortblock
Block: Gen-1 never decked (Manufacturer stamping still there, bored .040 over
Crank: Steel
Rods: Factory style, ARP Rod Bolts
Pistons: KB157 Hypereutectics (looking for 10.5:1 static compression)
Top End
Cam: Herbert Racing Hydraulic Roller CH7,
Adv. Dur. 287 Int. 285 Exh.
@.500. 242 Int. 246 Exh.
Lift .567 Int. .585 Exh.
Lobe Center 110
Centerline 106
@.500 Int. Open 14 Degrees Close 46
Exhaust Open 52 Degrees Close 11
Heads: Herbert Racing
Intake Valve: 2.02
Exhaust Valve: 1.60
Intake Runner: 210cc
Exhaust Runner: N/A (need to email them to find out for sure)
CFM: No clue
Carb: Quick Fuel Technologies
Slayer Series 750 CFM
Exhaust
Headers: Flowtech
Primaries: 1.5 in.
Collectors: 2.5 in.
Y-Pipe: 2.5 in.
Catback: 2.5 in.
If I managed to miss anything obvious please let me know.
I know the wealth of knowledge some of you all have (Five7kid). If anyone has any "YOU IDIOT!!" things to say please let me know. Also I would love any dyno software data you guys can provide. Thanks again for all of the help.
Hard to say without flow numbers on heads. Cam is huge for a 327, it will want to rev to 7500. Valvesprings are crucial as well as good lifters. Possibly 3/8 pushrod or tapered 5/16 style, or extra thick wall 5/16 for stability. Dual plane intake likely wont support the rpm so power will peak early and likely flatline til redline, upwards of 7000 rpm or so
Hard to say without flow numbers on heads. Cam is huge for a 327, it will want to rev to 7500. Valvesprings are crucial as well as good lifters. Possibly 3/8 pushrod or tapered 5/16 style, or extra thick wall 5/16 for stability. Dual plane intake likely wont support the rpm so power will peak early and likely flatline til redline, upwards of 7000 rpm or so
Thanks for the quick reply Orr! How would you go about fixing those problems? Cam just way too big? Go with something smaller? I'm trying to keep this thing drive able on the street...say rev limiter at 6500ish? I forgot to mention the lifters and the rest of the valvetrain. The lifters are also Herbert as well as the full roller rockers with a 1.5:1 ratio. Problem is the lifters are retrofit roller lifters have a suggested rpm max of 6000... Any suggestions? Last thing I want is a mismatched engine that's a pig on my wallet and the street. Still haven't assembled the motor so I haven't found pushrods yet.
For a 327 under 6500 rpm, i would stay with a cam around 224 deg at .050". Your selection is 242. Thats more for a 400" sbc.
Valvesprings need to be around 130-150 lbs seat pressure and 350-400 lbs open pressure at max lift to keep things happy. Depending on cam lobe design. More aggressive needs more spring pressure
For a 327 under 6500 rpm, i would stay with a cam around 224 deg at .050". Your selection is 242. Thats more for a 400" sbc.
Valvesprings need to be around 130-150 lbs seat pressure and 350-400 lbs open pressure at max lift to keep things happy. Depending on cam lobe design. More aggressive needs more spring pressure
The heads are supposedly assembled with springs to match the camshaft.
Maybe you can make sense of these stats? Here's a link to there page
Case in point, i run a cam somewhat similar to that in my 400" sbc and its pretty big. I turn 7200 rpm
Had a few 350-360" motors with 218/228 hotcams and 230/236 xfi's, and a 383 with a 230/245 and one with a 224/230. You can tell the 230 deg cam in a 360" sbc is a decent sized cam. Low end is reduced and all top end pull. Single plane or ported dual plane would be best
Case in point, i run a cam somewhat similar to that in my 400" sbc and its pretty big. I turn 7200 rpm
Had a few 350-360" motors with 218/228 hotcams and 230/236 xfi's, and a 383 with a 230/245 and one with a 224/230. You can tell the 230 deg cam in a 360" sbc is a decent sized cam. Low end is reduced and all top end pull. Single plane or ported dual plane would be best
Obviously I purchased a top end kit from Herbert. That being said I probably need to go back through them to get something different... Any of their sticks look respectable enough to change too?
Cam and heads are both way too big for a small mild 327 engine. That size heads and cam is what I would run a 12.5:1 4000-8000 rpm 327.
As you said, it's a street driving car... With a hot street 327, you want something like 170 to 185 cc heads, and cam in the 214 to 218 * @ .050 intake and 222 to 230* @ .050 exhaust, with just right around .500" lift
IMHO carb is also too big, a 600-670 cfm would be a better match.
And header tubes are too small.. Go with 1-5/8" tubes, 3" collectors.
If you use Fel pro 4.100 x .015 head gaskets, your compression will be 10.48:1
I use to play with the little short stroke engines A LOT. The 283, 302, and 327. The size and the short stroke hurts the low rpm power and the last thing you want to do to a street 327 is put big heads and big cam in it.
I would not have went with those heads even in a smaller size for that price though. At the $1100 for those, you could have got Brodix IK heads, pro-filer, etc.
They do list some flow numbers, but only starts at .400" lift which tells me the low lift on those heads suck. The flow on the low lift numbers are more important than the high lift, as your engine spends more time in the low lift range as the cam opens the valves and moves them to peak lift.
Which looks good on paper, but like I said, what is the flow at .050", .100", .200", .300"?
Even your monster cam only has .585" lift, so what good is great head flow at .700" lift when your cam can only open the valve to less than .600"
IMHO a set of vortec heads and a 220/230@.050" cam with .500"/.510" lift would give you much better results for street use.
With your heads and cam listed, that's a very high rpm set up. To make that work, I would use a vic jr. intake, 4500 stall converter, 4.56 gears and turn the thing to 8,000 rpm, but that would not work very well to drive around.
Man!... Feels like I've been had. I've been reading to many articles about 400ish horse 327s...in fact I was even led to believe that this combo could do that by the person I spoke to at Herbert when I ordered it... do I try and return it for their smaller 190cc port heads or do I see maybe about building a 350-400 shortblock Instead.
It will make power with those heads and cam. Just dont expect it to be a low rpm motor and be very streetable. It wont be either
You can crutch the big heads with an aggressive lobe tight lsa cam if you already have the heads and cant get rid of them
Well I do already have the Heads... In fact I have all of it except the Pistons. I got trigger happy last June and bought it, turns out to be an expensive mistake. Measure twice cut once seems to apply here. With that being said I need something with an LSA around 106 or so?
Yeah something like that. Do they have a 4-6 deg split cam like a 224/230 or 220/225 ish?
Try to get intake lift up in the .540-.560 range. No more than 1.6 rocker
Going to ask a dumb question that may seem like common knowledge. how does the rocker ratio effect lift? I know how it physically does it. say for instance they have a 220/225 split but the lift is only 465/470. would that put my in the ballpark max lift wise with 1.6 rockers?
Total valve lift like shown in summit, hot rod, etc is lobe lift x rocker ratio. Common sbc rocker ratio is 1.5 so that is what most sbc cams are listed with.
To find lobe lift it's....
total lift / rocker ratio = lobe lift
Now lobe lift x new rocker ratio = new total lift with bigger rocker arms.
Yeah the car rags will have you buying all kinds of parts. You can make 400 HP from a 327, that aint too hard, but in your case, you got to look at the power band.
It's easier to make big numbers up high in the RPM range but that does not help you on the streets.
If the engine makes peak at 8,000 rpm, with a good curve from 3500 to 8000, but you are running say 3.42 gears, and turning 3000 rpm at highway speeds, and 2000 rpm around town... It's gonna be a gas hog, that feels real soggy and in fact feel slower than stock.
For good street use you need to make power in the 1500 to 6500 rpm range.
I have a 355 with 200cc heads, 249/252@.050", .570"/.579" lift cam. Makes peak power at 7,000 rpm, I shift at 7200-7400 rpm. It's a dog off idle but the 3.89 gear and 3500 stall helps that out. The little bit I do drive it on the street, I get 7 mpg on 93 octane.
Here's some data points from the other end of the spectrum. Few seem to have much actual experience working a combination like this, still most are pretty quick to condemn my 357 sbc street build when looking at it on paper...
.040" 010 block
cast 3.48 crank
5.7" 5140 Pro Comp bushed rods $137/set
H345 hyper flattop pistons $95/set
rolled over using small dia solder, assembled "quench" measures .097"
solid roller Herbert CC6KF 251/261 @ .050 .625" 114 LSA ICL 110
Brodix -10 SP heads 300cfm (obsolete 410 sprint car parts)
Holley Strip Dominator
Carter 625
1-3/4" x 3" mid length headers, 3-1/2" single exh
dynamic comp is 8.27, engine cranks about 100psi on the starter
2500lb car, manual 4spd (no overdrive), 3.73, 28" tires
Sounds like a really lousy combination of parts on paper but here's the thing...it's a street/strip engine, so i'm looking for a fun compromise. Here's actual results from something that few would bother to build...
...in street mode using commonly available 87 octane regular gas, it gets a little over 20mpg on the hiway.
...in strip mode on the same 87 octane with a 200 shot of n2o, it's been 5.73 in the 1/8th with a 1.30 60'.
Who cares if it's not as snappy in hiway mode as it could be, it still pulls down 20mpg. The mileage mostly comes from a really low tension ring set and a wide LSA cam. All I have to do is crack the valve on the bottle and flip a switch on the dash, suddenly it's 700rwhp in a 2500lb package
The combination has evolved over the years. It started out using a Herbert CC6G solid roller, flat top claimer pistons and a set of old -8 spreadport Brodix heads i had sitting on the shelf. Lousy fuel mileage as one would expect, but we were amazed at how it came alive with just a small shot of n2o. I'm currently building the 5th version along these lines, the 4th version is outlined above. This time it's bigger heads, lower compression, forged flattops, and around 450 shot on regular gas thru a crossbar plate.
.055" below deck w/ a .039 gasket comes out to .094" quench, but squishing solder causes the piston to rock slightly, apparently added .003".
1.54 comp height
Cam- IO 14, IC 56, EO 63, EC 17...currently lashed at .012" cold
Alright everyone. After a few days repeatedly trying to get a hold of someone from Herbert Performance there has not been a response... kinda pissed but that doesn't get me anywhere. Soo I find myself looking for another Cam. I read an article in Super Chevy where they use a COMP Cam Xtreme Energy Stick, anyways the results were pretty impressive. The cam was only 236/242 Dur. and lift was only .501/.510 with a 110 LSA. the Heads seem WAY bigger than what I have. Any recommendations? Keep in Mind I would like to run Pump Gas 93 Octane. Also the Retrofit Roller Lifters say they're only good to 6,000... so I'm struggling a little here.
If you read thst write up again look at a few things.
1) solid flat tappet... Not a roller cam. You can not compare a flat tappet to a roller's duration as the roller cam has much faster/more aggressive ramps and accelerates the valves more. Also you can not compare a solid to a hyd. cam as the solid has a lash setting. That lash "eats" up some duration and lift.
That cam had .510" lift, with a .016" lash setting. Meaning it really only opens the valves .494" as the 1st .016" of cam lift is just taking up the slack (lash) in the valvetrain.
Also due to the lash settings, a solid cam's duration needs to be sized 4-8* more than a hyd. cam to get the same valve duration...
So based of the above that would make it around a 230/236 @.050" .494" lift hyd. flat tappet cam...
The you have to look at ramp speed on flat vs roller tappet cams.. Again some where around 5-10* with a flat tappet cam needing 5-10* more duration than a roller to get close to the same ramp speed.
This now puts it at around a 225/231* @.050"
2) look at the dyno chart on that right up... The heart of the power curve is 3500-6500 rpm... Again this will not be a fun street use engine
If you read thst write up again look at a few things.
1) solid flat tappet... Not a roller cam. You can not compare a flat tappet to a roller's duration as the roller cam has much faster/more aggressive ramps and accelerates the valves more. Also you can not compare a solid to a hyd. cam as the solid has a lash setting. That lash "eats" up some duration and lift.
That cam had .510" lift, with a .016" lash setting. Meaning it really only opens the valves .494" as the 1st .016" of cam lift is just taking up the slack (lash) in the valvetrain.
Also due to the lash settings, a solid cam's duration needs to be sized 4-8* more than a hyd. cam to get the same valve duration...
So based of the above that would make it around a 230/236 @.050" .494" lift hyd. flat tappet cam...
The you have to look at ramp speed on flat vs roller tappet cams.. Again some where around 5-10* with a flat tappet cam needing 5-10* more duration than a roller to get close to the same ramp speed.
This now puts it at around a 225/231* @.050"
2) look at the dyno chart on that right up... The heart of the power curve is 3500-6500 rpm... Again this will not be a fun street use engine
Okay now I'm really confused. So that solid Cam is even smaller than I thought and still got those crazy numbers??? So how does that translate roughly to a Hydraulic Roller Cam? Is it even possible? Those AFR Heads they used seem WAY bigger than what I am using and still got amazing numbers... so do I need to choose a cam somewhere from the 220-240 duration? and lift just don't care about because I can always get different ratio roller rockers?
What are your opinions on these? Are they at least in the ballpark?
... maybe run some numbers and help me put together some ballpark Hp/Tq figures on a Small Journal 327 I'm building..
Running the numbers isn't all that difficult but what you've failed to mention (from what I've read) is the purpose of the vehicle? Seems the general assumption is street not track and the efforts of the contributions here are steering you in that direction. Save for Granny's example with the nitrous cam.
I have a couple of questions and would grind some of your data through DynoSim so you can see the effects of different cams with the heads you've got. Remember that the cam you ultimately select will be intimately tied to the compression ratio and it's important that you build the engine accordingly.
What is the intended purpose of this engine? Street. Race only? A combination?
Do you have the flow numbers and other relevant test data for those heads? Chamber volume (cc)?
Is fuel economy important?
For the record, the suggestions regarding cams in the 224-230 range are entirely likely to produce 400 crankshaft horsepower even with the smallish cubes. The torque will be down regardless (compared to a 350 for example) simply due to the decreased stroke. The upgraded rods should allow the exploration of rpms to 6000 or so but certainly not in an open road race event where you might keep it between peak torque and peak horsepower for extended periods. Drag racing lets you get away with higher rpms as it's for short bursts. This isn't to say that more than one person has spit a connecting rod out the side of the block at the drag strip.
Keep in mind that those dyno numbers you're seeing in the magazines are typically of a "gross" horsepower nature. That is to say, the engine isn't running any accessories (water pump, alternator or power steering pump) and the headers are such that duplicating their contribution to performance would be next to impossible in the chassis of your car.
(your 1st selection above) in a Vortec headed 350 with excellent results from a performance, driveability and fuel economy standpoint. Peak power was in /around 5500-5700 rpm. Idled well with 12-13" vacuum. 20+ mpg hiway with a 700R4 and 3.73 rear gear. That particular cam liked about 10:1 static compression ratio.
Alright everyone. After a few days repeatedly trying to get a hold of someone from Herbert Performance there has not been a response... kinda pissed but that doesn't get me anywhere.
The last Herbert roller i bought actually shipped from...
Ruben Cams
Ruben Gabriel
1412 S. Central Park Ave
Anaheim, CA 92802
714-491-2267
I suspect Ruben was the cam grinder for Chet Herbert, probably opened his own shop as Chet's operation closed down. I believe Doug Herbert's operation (Chet's son) is based in NC
.055" below deck w/ a .039 gasket comes out to .094" quench, but squishing solder causes the piston to rock slightly, apparently added .003".
1.54 comp height
Cam- IO 14, IC 56, EO 63, EC 17...currently lashed at .012" cold
I couldn't get those cam event numbers to jive with anything I could find in a similar grind. Comps similar nitrous grind puts the IC event around 80 something degrees. Herbert doesn't list the any cam card information. I'd still like to run your dynamic compression ratio numbers through my calculator.
That .055" piston to deck value is a long ways down. Any reason you went this route?
Running the numbers isn't all that difficult but what you've failed to mention (from what I've read) is the purpose of the vehicle? Seems the general assumption is street not track and the efforts of the contributions here are steering you in that direction. Save for Granny's example with the nitrous cam.
I have a couple of questions and would grind some of your data through DynoSim so you can see the effects of different cams with the heads you've got. Remember that the cam you ultimately select will be intimately tied to the compression ratio and it's important that you build the engine accordingly.
What is the intended purpose of this engine? Street. Race only? A combination?
Do you have the flow numbers and other relevant test data for those heads? Chamber volume (cc)?
Is fuel economy important?
For the record, the suggestions regarding cams in the 224-230 range are entirely likely to produce 400 crankshaft horsepower even with the smallish cubes. The torque will be down regardless (compared to a 350 for example) simply due to the decreased stroke. The upgraded rods should allow the exploration of rpms to 6000 or so but certainly not in an open road race event where you might keep it between peak torque and peak horsepower for extended periods. Drag racing lets you get away with higher rpms as it's for short bursts. This isn't to say that more than one person has spit a connecting rod out the side of the block at the drag strip.
Keep in mind that those dyno numbers you're seeing in the magazines are typically of a "gross" horsepower nature. That is to say, the engine isn't running any accessories (water pump, alternator or power steering pump) and the headers are such that duplicating their contribution to performance would be next to impossible in the chassis of your car.
(your 1st selection above) in a Vortec headed 350 with excellent results from a performance, driveability and fuel economy standpoint. Peak power was in /around 5500-5700 rpm. Idled well with 12-13" vacuum. 20+ mpg hiway with a 700R4 and 3.73 rear gear. That particular cam liked about 10:1 static compression ratio.
Hey there Skinny. I will say that the primary purpose will be touring with the occasional rampage through the back roads. Maybe just maybe a few trips down the quarter mile or a Track Day event. I'm not a great driver. I have never made a quarter mile pass ever. Mileage is not super important. I really only need to have a range of about 140-150 miles. So I guess the short answer to your question is a combination.
The Flow numbers posted on their website are as follows. I know the numbers aren't fantastic...
.400 lift 240/183
.500 lift 264/199
.600 lift 278/208
.700 lift 287/213
.800 lift 290/216
the Chambers are 64cc.
210cc Intake Runners
No Idea on Exhaust Runner cc I'm gonna guess around 80?
The static compression I was going after is 10.5:1 maybe 11? I've been told that you want at least 8:1 Dynamic Compression. Is this Correct? I would also love to be able to run 93 Octane.
Connecting Rod wise right now they're stock with ARP bolts. Will those not be good enough for this power level?
I'm gonna see if I can find 1 5/8 headers with a 3 inch exhaust the rest of the way.
That's about all the information I can glean from their website. I understand that Engine Dyno Data should be taken with a grain of salt. If you need any additional information I would be happy to supply it. I really appreciate you taking the time to crunch the numbers for me.
The Flow numbers posted on their website are as follows. I know the numbers aren't fantastic...
.400 lift 240/183
.500 lift 264/199
.600 lift 278/208
.700 lift 287/213
.800 lift 290/216
I see that however as Night Rider points out...
Originally Posted by Night rider327
...Which looks good on paper, but like I said, what is the flow at .050", .100", .200", .300"?
It'll be tough to get any kind of meaningful data out of Dyno Sim without numbers that cover more relevant lift points. Test pressure and test bore size are also important so we're comparing apples to apples.
I'll look around to see if there isn't an independent data base that has run a test on your heads. Stan Weiss at
It'll be tough to get any kind of meaningful data out of Dyno Sim without numbers that cover more relevant lift points. Test pressure and test bore size are also important so we're comparing apples to apples.
I'll look around to see if there isn't an independent data base that has run a test on your heads. Stan Weiss at
has a lot results although i can't remember seeing a set of Herbert heads in there.
I know...Again one of the other reasons I'm not impressed with Herbert at all. I will never be using them again. That's all I have. I guess I can try and find a similar set of heads with close to the same values at the points I listed before and see if they apply... Thanks again for all the digging
Check out what a Vortec head flows at .400" to 500"-550". I think your Herbert heads have better numbers.
That said, they undoubtedly don't do better at low lift levels. That leaves you, with those heads, to build to their strength.
Put as much lift into what you pick as a cam without too much overlap. I know of a few grinds in XFI range of lobes at Comp that can provide that. I know Orr has experience with those lobes. To shift at 6500 with the shorter stroke 327, sound hardware and a steel crank? Sure. I might not do a Cannon Ball run with it but at the drag strip now and again. Yes.
Do you guys think the summit racing 170cc aluminum heads with a little clean up would work well? I bought them to use on a 350 and they had trickflow paperwork in them if I recall. Ended up doing 195 tf's instead.
Check out what a Vortec head flows at .400" to 500"-550". I think your Herbert heads have better numbers.
That said, they undoubtedly don't do a better a low lift levels. That leaves you, with those heads, to build to their strength.
Put as much lift into what you pick as a cam without too much overlap. I know of a few grinds in XFI range of lobes at Comp that can provide that. I know Orr has experience with those lobes. To shift at 6500 with the shorter stroke 327, sound hardware and a steel crank? Sure. I might not do a Cannon Ball run with it but at the drag strip now and again. Yes.
I thought the whole point of the XFI series was to grind it for fuel injection? It doesn't have the extra air flow signal to run a carb?
Xfi shelf cams are generally targeting efi motors with the wide lsa. Custom ordered, those cams work well with todays intake ports in good flowing heads, and work better with the tighter lsa say 108-110
Xfi shelf cams are generally targeting efi motors with the wide lsa. Custom ordered, those cams work well with todays intake ports in good flowing heads, and work better with the tighter lsa say 108-110
ohh i get it now... Just gotta see what that custom stick will run me...
Well I called Comp today and I spoke with Alex. He recommended the XR282HR grind, 110LSA, .510/.520 lift with 1.5, 230/236 dur. at .50? what are the major differences between this grind and the XR270HR 110 LSA .495/.502 lift with 1.5, 218/224 at .50? Besides the obvious specification differences I guess I don't understand How all this applies to the power curve. Does it Shorten it? Broaden it? Move it Higher in the RPMs or drop down to more pedestrian levels?
That's a complicated subject to cover in a forum such as this.
I recommend getting a couple fo books on building high performance engines. One of my personal favourites is David Vizard's How to Build Max Performance Chevy Small Blocks on a Budget.
Lots of really good tech in there and explained in an understandable way. It'll go a long ways towards your getting a better handle on this particular subject.
As for the differences, in the attached graph is my current cam (which is more or less Comps XR276HR but built with selected XFI lobes from Comps catalog) compared to Comps XR288HR. You can see how the little cam makes better torque and hp in the lower rpm range and peaks well before the larger cam. The larger cam makes considerably more power past peak and especially past 6000 rpm. I shift at 6500 (it's a gearing thing) so selecting the 288 for the drag strip should make for a faster car. That's provided I have the torque converter and gearing to take advantage of the higher rpm capabilities.
As a gen idea
Narrow LSA will give you a smaller power band, but brings peak RPM down some and gives you more peak HP/TQ
Where a wide LSA cam will have a wider overall power band, but the peak points will be higher up in the rpm band, your peak HP/TQ will be a little less.
Narrow LSA will also raise cylinder pressure/DCR
Wide LSA will lower cylinder pressure/DCR.
Now like Skinny said, this is just a drop in the bucket on how and why the numbers changing how the cam acts. You have a lot more to look at and understand. Duration also effects your power band and cylinder pressure.
That's a complicated subject to cover in a forum such as this.
I recommend getting a couple fo books on building high performance engines. One of my personal favourites is David Vizard's How to Build Max Performance Chevy Small Blocks on a Budget.
Lots of really good tech in there and explained in an understandable way. It'll go a long ways towards your getting a better handle on this particular subject.
As for the differences, in the attached graph is my current cam (which is more or less Comps XR276HR but built with selected XFI lobes from Comps catalog) compared to Comps XR288HR. You can see how the little cam makes better torque and hp in the lower rpm range and peaks well before the larger cam. The larger cam makes considerably more power past peak and especially past 6000 rpm. I shift at 6500 (it's a gearing thing) so selecting the 288 for the drag strip should make for a faster car. That's provided I have the torque converter and gearing to take advantage of the higher rpm capabilities.
274 vs 288
Thats awesome man! I appreciate you posting that up for me! Helps me wrap my head around this a lot better.
Okay just a couple final questions and I think I can put this thing to bed for a while. Does anyone think an upgraded set of rods is necessary at the power level I'm trying to achieve? Also oes anyone think it will be worthwhile to have the cam I have now reworked to specs that make sense for my heads, or do I just get another stick all together? Just to remind everyone here are the specs I have now. If I were to have the duration shorted to say 218/224 at .500 what do you think I should have the lift be? .570/.575? Or even shorter than that? Will the Geometry of the Lobe not make sense? Again I appreciate everything you all have done to help me work this out.
Top End
Cam: Herbert Racing Hydraulic Roller CH7,
Adv. Dur. 287 Int. 285 Exh.
@.500. 242 Int. 246 Exh.
Lift .567 Int. .585 Exh.
Lobe Center 110
Centerline 106
@.500 Int. Open 14 Degrees Close 46
Exhaust Open 52 Degrees Close 11
Cheap upgrade would be scat i beam with 7/16 bolts
I had been told by a number of other people that the rods should be fine I just wanted another opinion. Okay So as far as the cam goes then I'm looking at the XFI series 260XFI HR13 with an LSA of 110 Intake Centerline of 106?
01-27-2016, 06:27 PM
