It really don't matter in a serious race only build, just bump the octane rating on your fuel until your out of detonation. On a street, pump gas motor I think you really need to consider it.
Choosing a solid roller cam
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From: Pettis Performance 565 with two stages of Nitrous Supply nitrous 1.082, 4.61 at 155, 7.17 at 192
Call Reher-Morrison, Pat Musi, or anybody that builds street and strip engines and ask them what the DCR of any of their engines are and I will bet you they will not know. It is just not important.
It is virtually impossible to predict what the DCR of an engine really is, too many variables. Even if you could predict it within a few % every engine would react differently to how much DCR you could run on pump gas. The difference between a small block Chevy's bore and a big block Chevy's bore alone makes the DCR an unimportant figure, then you throw in things like combustion chamber efficiency (a much more important variable than DCR) quench, fuel separation, swirl, intake distribution, etc, etc.
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From: Reno Nevada
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I had a 355 SR splayed cap 10.7 CR, ported 200cc probably closer to 210 - 215 cc with 2.055/1.6 Pro flow manley valves, team "G" single plane. 750 EDL VS carb. The Crane SR 232/240 with 1.6's.
Very soggy below 2000 rpm. 2500 - 7500 it ran great. It would have been a great 5 speed motor. At the time I had a 3800 stall 9.5 inch 700R4 lockup with a 4.11 as a crutch
For a hot 355 -377 ci I would use a minimum of 195cc
This is a picture of my Crane Street 232/240 compared to the much more aggresive 236/242 I used in my second 383 build. The 232 could not deal with 11.24 compression
Very soggy below 2000 rpm. 2500 - 7500 it ran great. It would have been a great 5 speed motor. At the time I had a 3800 stall 9.5 inch 700R4 lockup with a 4.11 as a crutch
For a hot 355 -377 ci I would use a minimum of 195cc
This is a picture of my Crane Street 232/240 compared to the much more aggresive 236/242 I used in my second 383 build. The 232 could not deal with 11.24 compression
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From: All humans are vermin in the eyes of Guru VA
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Do you really think I can use the flow from larger heads?
I may be totally wrong here but I think that the flow from the AFR heads is exceptional enough that they will support the 355ci in the same way as bigger volume ported heads elsewhere with additional benefits of increased velocity.
Remember the AFR 195s flow almost as much as your Dart 227cc heads:
Dart:
Flow, Intake: 309cfm @ .700” lift / 28”
Flow, Exhaust: 226cfm @ .700” lift / 28”
AFR 195 CNC:
Intake, 300cfm @ .6
Exhaust, 225cfm @.6
The AFR 180 CNC package flows almost as well as Dart 215cc heads:
Dart 215cc
Flow, Intake: 276cfm @ .600” lift / 28”
Flow, Exhaust: 180cfm @ .600” lift / 28”
AFR 180CNC
Intake, 270cfm @ .5
Exhaust, 217cfm @ .5
I may be totally wrong here but I think that the flow from the AFR heads is exceptional enough that they will support the 355ci in the same way as bigger volume ported heads elsewhere with additional benefits of increased velocity.
Remember the AFR 195s flow almost as much as your Dart 227cc heads:
Dart:
Flow, Intake: 309cfm @ .700” lift / 28”
Flow, Exhaust: 226cfm @ .700” lift / 28”
AFR 195 CNC:
Intake, 300cfm @ .6
Exhaust, 225cfm @.6
The AFR 180 CNC package flows almost as well as Dart 215cc heads:
Dart 215cc
Flow, Intake: 276cfm @ .600” lift / 28”
Flow, Exhaust: 180cfm @ .600” lift / 28”
AFR 180CNC
Intake, 270cfm @ .5
Exhaust, 217cfm @ .5
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What most people fail to realize is:
It is the total port volume including the single manifold track not just the head cc that is dead stopped air space that has to get moving into the cylinder. Just as a reference you can probably put about 10cc's of water in a table spoon.
I had 37 ford coupe street rod 337ci with a dual 660 cfm tunnel ram P&P cast iron 200cc hogged out 238/248 solid cam 6.250 rods back in the 80's.
Fuel separation is more of a function of keeping the carb CFM low and plenum volume low in a single plane 355 ci. I'm a 650 DP carb or 750 VS max carb person on small plenum volume single planes on 383 or less ci
It is the total port volume including the single manifold track not just the head cc that is dead stopped air space that has to get moving into the cylinder. Just as a reference you can probably put about 10cc's of water in a table spoon.
I had 37 ford coupe street rod 337ci with a dual 660 cfm tunnel ram P&P cast iron 200cc hogged out 238/248 solid cam 6.250 rods back in the 80's.
Fuel separation is more of a function of keeping the carb CFM low and plenum volume low in a single plane 355 ci. I'm a 650 DP carb or 750 VS max carb person on small plenum volume single planes on 383 or less ci
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Wow think I'll shelve the 427 if you can make 550 HP and 500ft/lbs with a 355ci. THat's what my 406ci makes with 220cc heads and 2.08 valves 
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From: All humans are vermin in the eyes of Guru VA
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What most people fail to realize is:
It is the total port volume including the single manifold track not just the head cc that is dead stopped air space that has to get moving into the cylinder. Just as a reference you can probably put about 10cc's of water in a table spoon.
I had 37 ford coupe street rod 337ci with a dual 660 cfm tunnel ram P&P cast iron 200cc hogged out 238/248 solid cam 6.250 rods back in the 80's.
Fuel separation is more of a function of keeping the carb CFM low and plenum volume low in a single plane 355 ci. I'm a 650 DP carb or 750 VS max carb person on small plenum volume single planes on 383 or less ci
It is the total port volume including the single manifold track not just the head cc that is dead stopped air space that has to get moving into the cylinder. Just as a reference you can probably put about 10cc's of water in a table spoon.
I had 37 ford coupe street rod 337ci with a dual 660 cfm tunnel ram P&P cast iron 200cc hogged out 238/248 solid cam 6.250 rods back in the 80's.
Fuel separation is more of a function of keeping the carb CFM low and plenum volume low in a single plane 355 ci. I'm a 650 DP carb or 750 VS max carb person on small plenum volume single planes on 383 or less ci
I have a 650cfm carb, I might try and get one of the mainbodies without the choke horn.
I was actually thinking about something like a demon Removable venturi carburator, and putting in the smallest primary venturis possible.
What is your opinion of the Team G versus Edelbrock Victor Jr?
Last edited by Guru_4_hire; Mar 30, 2008 at 09:16 PM.
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From: All humans are vermin in the eyes of Guru VA
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the DD2K thing is notoriously optomistic, only relevant as far as a planning tool to me.
Last edited by Guru_4_hire; Mar 30, 2008 at 09:24 PM.
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Near racing motors can make 1.3 ish foot pounds per ci. On dynos I have seen 396 and 406 making 500 to 550. to get 600 foot pounds requires 427 - 441 ci with 12 -18 degree heads flowing 350 - 400 cfm.
Motorhead. I've been helping build a Ferrari 3 liter V-12 at the shop. The heads were $15K bare we mounted it on the dyno Friday. They are having a set of dyno headers made before it can be tested
Motorhead. I've been helping build a Ferrari 3 liter V-12 at the shop. The heads were $15K bare we mounted it on the dyno Friday. They are having a set of dyno headers made before it can be tested
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From: All humans are vermin in the eyes of Guru VA
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I dont know.
383s with AFR 195s are making like 525+hp with 280 or 288 degree Hyd. Rollers, before they went to the eliminator heads. Their 180cc heads now flow what their old 195cc heads did. So........ 475+ maybe?
Tell you what when I finally get the damn thing built I will let you know.
383s with AFR 195s are making like 525+hp with 280 or 288 degree Hyd. Rollers, before they went to the eliminator heads. Their 180cc heads now flow what their old 195cc heads did. So........ 475+ maybe?
Tell you what when I finally get the damn thing built I will let you know.
Last edited by Guru_4_hire; Mar 30, 2008 at 10:01 PM.
Racer
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From: Pace FL
Ignore DCR, virtually worthless equation. You will never hear a real cam designer even talk about DCR, some will ask you what it even means. There are wayyyyyyy too many variables that would go into figuring a true DCR that it makes it almost completely worthless to even discuss it. If you have noticed it is rarely talked about on any of the performance boards and is laughed at on the serious performance boards.
Race engine builders ("serious") don't worry about the # since they avoid this variable with octane numbers.
For the street engine (93 octane) it will tell you if you are over cammed, too high of static compression, ect...
All said, it is only a useful tool and should be treated as such.
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Near racing motors can make 1.3 ish foot pounds per ci. On dynos I have seen 396 and 406 making 500 to 550. to get 600 foot pounds requires 427 - 441 ci with 12 -18 degree heads flowing 350 - 400 cfm.
Motorhead. I've been helping build a Ferrari 3 liter V-12 at the shop. The heads were $15K bare we mounted it on the dyno Friday. They are having a set of dyno headers made before it can be tested
Motorhead. I've been helping build a Ferrari 3 liter V-12 at the shop. The heads were $15K bare we mounted it on the dyno Friday. They are having a set of dyno headers made before it can be tested
Last edited by Little Mouse; Mar 30, 2008 at 10:11 PM.
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
3000cc is @180 ci add double over head roller cams and two spark plugs per cylinder with twin ignitions of 12 wires each. Did you know that the F1 motors (not this one) that can do the 18000 - 19000 rpm idle at 4500 rpm and that is with the modern variable cam electronic cam timing?
This type motor back in the day won the 24 hours of Le'Mans
You should see some of the older race cars up close!!!!!!!!!!!!!!!!!!!!
This type motor back in the day won the 24 hours of Le'Mans
You should see some of the older race cars up close!!!!!!!!!!!!!!!!!!!!
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
I dont know.
383s with AFR 195s are making like 525+hp with 280 or 288 degree Hyd. Rollers, before they went to the eliminator heads. Their 180cc heads now flow what their old 195cc heads did. So........ 475+ maybe?
Tell you what when I finally get the damn thing built I will let you know.
383s with AFR 195s are making like 525+hp with 280 or 288 degree Hyd. Rollers, before they went to the eliminator heads. Their 180cc heads now flow what their old 195cc heads did. So........ 475+ maybe?
Tell you what when I finally get the damn thing built I will let you know.
Just yanking chains tonight 
Guru_4_hire, get the new 195's and use the XR274R solid roller @ 10:1 cr and you will have a nice little motor there
gkull love the vintage racing machines, going to get into it myself. Going to my first track day in a couple of weeks
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
I would vote for the Crane street SR 232/240
My first play day is 5-6 April 4.2 mile course. I've been nice to my 434. I have had the rev limiter at 7000 rpm. I generally short shift it because I have a traction problems even with big slicks.
That is where a little 355 motor like Guru would shine. You can floor it and scream
Easing into a gas petal to go faster is harder to do........... Like your 406 You have to learn not to floor it in the lower two gears
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From: All humans are vermin in the eyes of Guru VA
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Wouldnt that be nice. Floor it and scream.
Whats funny is that I have been looking at this autocross thing as a purpose as well. I could in theory do the entire course and never shift out of first gear. Especially if I take steps to maintain the limited low RPM torque, with an M22W transmission and a 3.73 rearend, I could drive it all the way up to 58 MPH, with gobs of torque on Tap because of the 2.56 first gear and 3.73 rearend.
How are the 195s going to operate in the 1000-3000 range, I am halfway sold.
Whats funny is that I have been looking at this autocross thing as a purpose as well. I could in theory do the entire course and never shift out of first gear. Especially if I take steps to maintain the limited low RPM torque, with an M22W transmission and a 3.73 rearend, I could drive it all the way up to 58 MPH, with gobs of torque on Tap because of the 2.56 first gear and 3.73 rearend.
How are the 195s going to operate in the 1000-3000 range, I am halfway sold.
Last edited by Guru_4_hire; Mar 31, 2008 at 08:18 AM.
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From: Watkinsville, GA and Glen Cove, NY
I think the basic problem with DCR the way most use it is trying to figure what compression can we get away with to avoid detonation. So we think we can run a big cam and high static compression. Problem is, we run that big cam and then spin the engine high, and those cylinders start filling and bingo, we detonate at high rpm's. I agree with the statements that DCR's are irrelevant. I have seen some big blocks with real low DCR's run pretty good.
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From: All humans are vermin in the eyes of Guru VA
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Thought about it during a walk. And AFR 195s it is.
Now to find some used flat top pistons, and team G intake manifold.
The crankshaft and heads I am going to buy new.
Now to find some used flat top pistons, and team G intake manifold.
The crankshaft and heads I am going to buy new.
Last edited by Guru_4_hire; Mar 31, 2008 at 10:53 AM.
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) tunnel ram with two 660s. All he had for pistons were a new set of Mcquay Norris Cast dome 11.0 pistons from the automotive wharehouse/machine shop we both worked at in the 1970s. There were no such thing as hyper pistons in the 70s if you had a set you would have super duper pistons. I guess if your going to turn your 355, 7000 constant rpm on a oval track or put this funny new gas stuff in it may want to hunt up a set of forged pistons, nice thing about cast hyper pistons they are light and low cost.
Last edited by Little Mouse; Mar 31, 2008 at 04:36 PM.
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From: All humans are vermin in the eyes of Guru VA
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I bid on some used SRPs.
If that doesnt work I will look at the best speed pros money can buy.
I wonder what a set of speedpros weigh compared to a similiar forged piston.
(I bet people would look at a set of speed pros on top of my 6" billet crower rods.)
If that doesnt work I will look at the best speed pros money can buy.
I wonder what a set of speedpros weigh compared to a similiar forged piston.
(I bet people would look at a set of speed pros on top of my 6" billet crower rods.)