My Budget 250 build
- Thread starter lavron
- Start date
lavron
Well-known member
I got my reply back from Clay Smith Cams on recommendations, H-274-8-B;
274/274 224/224 .450/.450 108* 1800-5700 RPM range
Excellent low to mid-range performance cam, Fair vacuum, lopey idle, great with 2V conversions Manual transmission or stall converter recommended.
And the 262-70H Schnider cam I listed earlier;
262/270 208/214 .435/.442 110* 1800-5500 RPM range
No description with the Schnider cam on what to expect on the idle, vacuum, etc.
Does anyone know how different theses two cams would be?
Anyone have any thoughts they could give me or preferences?
I am assuming that both will run the advance on the distributor ok and I am going to be running the early 250 timing gear set, if that makes a difference. I did give both companies the same info on intended use etc. (no track, highway/occasional daily driver).
I guess I am looking for some of the sage advice from the experts here
before I order one of these.
The only other consideration is I am going to be ordering a timing set from Clay Smith but the shipping costs are a wash between the two.
See Ya,
Mike
274/274 224/224 .450/.450 108* 1800-5700 RPM range
Excellent low to mid-range performance cam, Fair vacuum, lopey idle, great with 2V conversions Manual transmission or stall converter recommended.
And the 262-70H Schnider cam I listed earlier;
262/270 208/214 .435/.442 110* 1800-5500 RPM range
No description with the Schnider cam on what to expect on the idle, vacuum, etc.
Does anyone know how different theses two cams would be?
Anyone have any thoughts they could give me or preferences?
I am assuming that both will run the advance on the distributor ok and I am going to be running the early 250 timing gear set, if that makes a difference. I did give both companies the same info on intended use etc. (no track, highway/occasional daily driver).
I guess I am looking for some of the sage advice from the experts here
before I order one of these.The only other consideration is I am going to be ordering a timing set from Clay Smith but the shipping costs are a wash between the two.
See Ya,
Mike
"...only other consideration..."
and 6v (cfm?) on pump gas & I 4get after 6 pages, 200 posts'n 3 yrs
what head/valves, etc...
The guy I wrk 4 sez Schnider custom grinds a cam
for the same price most have offa da shelf...
guys here may dial it in 4 U and schnider supplys?
U trust design by committee
and 6v (cfm?) on pump gas & I 4get after 6 pages, 200 posts'n 3 yrs
what head/valves, etc...
The guy I wrk 4 sez Schnider custom grinds a cam
for the same price most have offa da shelf...
guys here may dial it in 4 U and schnider supplys?
U trust design by committee
The Clay Smith cam has 8 degrees of .050" overlap.
I can tell you from the 300 I put together with a cam with 8 degrees of overlap that the idle didn't become smooth till 900 rpm and made 17 inHg vacuum.
On the smaller 250 it will be more pronounced, rougher idle and less vacuum. I suspect the engine won't start pulling till 1500 rpm.
The upper rpm of 5700 is about right if the head has been ported and larger valves otherwise the power band gets cut short because the head won't breath but the 108 LSA will provide a very strong midrange.
This is not a good cam if you are looking for fuel mileage.
The Schneider cam has -9 degrees of overlap (17 less than the Clay Smith) and will idle smoothly and make torque from just above an idle out to at least 4500 and maybe 5000 rpm depending on head work. The torque curve will be flat. Fuel mileage should be good.
The Clay cam comes on more suddenly with a strong midrange then drops off.
The Clay cam will need a lot more initial timing than the Schneider which means the mechanical advance will need to be shortened
I can tell you from the 300 I put together with a cam with 8 degrees of overlap that the idle didn't become smooth till 900 rpm and made 17 inHg vacuum.
On the smaller 250 it will be more pronounced, rougher idle and less vacuum. I suspect the engine won't start pulling till 1500 rpm.
The upper rpm of 5700 is about right if the head has been ported and larger valves otherwise the power band gets cut short because the head won't breath but the 108 LSA will provide a very strong midrange.
This is not a good cam if you are looking for fuel mileage.
The Schneider cam has -9 degrees of overlap (17 less than the Clay Smith) and will idle smoothly and make torque from just above an idle out to at least 4500 and maybe 5000 rpm depending on head work. The torque curve will be flat. Fuel mileage should be good.
The Clay cam comes on more suddenly with a strong midrange then drops off.
The Clay cam will need a lot more initial timing than the Schneider which means the mechanical advance will need to be shortened
lavron
Well-known member
pmuller9":1wf0zl9w said:
Thanks to this kind of information I am looking for it is a big help and now I am leaning more toward one of them. :roll:
I was out tinkering around today and sat the carbs down on the motor, I don't think I had ever mocked them up on the car yet, front one is getting a little tight on the hood I think so hopefully it will clear, I am going to make some carb hats and duct over to the filter.
See Ya,
Mike
The cam needs to take advantage of the triple carbs.
The Schneider cam listed it too mild.
You need something in between the Schneider and Clay Smith cams.
I would recommend a 220 degree single profile cam with either a 110 or 112 degree LSA depending on how smooth an idle you want.
The Howards 280998-10 is a high lift, 221 duration cam on a 110 LSA. The high lift will provide plenty of torque.
https://www.howardscams.com/hydraulic-f ... -280998-10
https://www.summitracing.com/parts/hrs-280998-10
I see what happened to Clay Smith.
Their off the shelf profiles jumps from 214 to 224 with nothing in between.
They figured use the 224 and put it on a tight 108 LSA to improve low to midrange torque.
The problem with that approach is that the tight LSA with the long duration cam lobes increases the overlap to the point where the power comes on way late and comes on abruptly.
It can be a fun power band if that is what a person wants.
What octane fuel will you be using?
The Schneider cam listed it too mild.
You need something in between the Schneider and Clay Smith cams.
I would recommend a 220 degree single profile cam with either a 110 or 112 degree LSA depending on how smooth an idle you want.
The Howards 280998-10 is a high lift, 221 duration cam on a 110 LSA. The high lift will provide plenty of torque.
https://www.howardscams.com/hydraulic-f ... -280998-10
https://www.summitracing.com/parts/hrs-280998-10
I see what happened to Clay Smith.
Their off the shelf profiles jumps from 214 to 224 with nothing in between.
They figured use the 224 and put it on a tight 108 LSA to improve low to midrange torque.
The problem with that approach is that the tight LSA with the long duration cam lobes increases the overlap to the point where the power comes on way late and comes on abruptly.
It can be a fun power band if that is what a person wants.
What octane fuel will you be using?
Why does everyone use stock Ford 302 valve springs? Any of the above cams will require springs with close to 110# seat & 250-290# open.
Schneider also has a 270-280 cam 214@.050" & 222@.050 with a lift .440.495" depending on rocker arm ratio.You could get a lot more from a smaller cam with 1.6 or 1.65 rocker arms.
From what i see Schneider & Howard look like your best choices.
Crower also has many profiles.
The guys from the big six group have all done their homework & have tested all of the above.
Schneider also has a 270-280 cam 214@.050" & 222@.050 with a lift .440.495" depending on rocker arm ratio.You could get a lot more from a smaller cam with 1.6 or 1.65 rocker arms.
From what i see Schneider & Howard look like your best choices.
Crower also has many profiles.
The guys from the big six group have all done their homework & have tested all of the above.
lavron
Well-known member
Thanks again for the response guys.
I don't want too lumpy of an idle so I guess the 110 would be the better choice there (part of me wants the lope part thinks it should be smooth, maybe I am getting old).
I did because I think that recommendation came from the Ford Falcon Performance Handbook and they were in my budget.
Standard premium pump gas I think the local station has ethanol-free 91 octane, also I said wrong on compression ratio it is actually 9.5-9-6, I had forgotten the machinist had recalculated it when he did the head work.
And highway driving/trips are the main use I can't really qualify anything as a daily driver because I only leave the house once or twice a week :roll: (this was even before the virus lockdown) But the car will not be raced, at least probably not, took me too long to get to build it.
See Ya,
Mike
pmuller9":1to46lnc said:
I don't want too lumpy of an idle so I guess the 110 would be the better choice there (part of me wants the lope part thinks it should be smooth, maybe I am getting old).
wsa111":1to46lnc said:
I did because I think that recommendation came from the Ford Falcon Performance Handbook and they were in my budget.
pmuller9":1to46lnc said:
Standard premium pump gas I think the local station has ethanol-free 91 octane, also I said wrong on compression ratio it is actually 9.5-9-6, I had forgotten the machinist had recalculated it when he did the head work.
And highway driving/trips are the main use I can't really qualify anything as a daily driver because I only leave the house once or twice a week :roll:
(this was even before the virus lockdown) But the car will not be raced, at least probably not, took me too long to get to build it.See Ya,
Mike
You are at a point beyond the ford six handbook.
You need valve spring recommended by you cam grinders recommendations.
With higher ratio rocker you can make a smaller cam look bigger.
When you make your cam choice, i believe its time to start a new topic.
You need valve spring recommended by you cam grinders recommendations.
With higher ratio rocker you can make a smaller cam look bigger.
When you make your cam choice, i believe its time to start a new topic.
I didn't mean to indicate that, but now U bring it up...what could "go below" ?lavron":1bsz40lz said:Maybe I do need a new thread
It is a '72 flat-top "M" log head with the seats recut to fit larger '78+ intake valves and hardened exhaust valve seats.
See Ya,
Mike
Would you put somea dat in a 'sig' ?
There's something to be said abt '1 continious thread'. 'N I remember w/the resto salesman
from Lakeland 'build threads' were OKed for this forum. I was just askin for a memory re-fresh.
Thanx !
BTW: on the 'flat top "M" - was that just the 3, 4 yrs '69 - '72 ?
Mike, the lobe lift on that cam is .313"lavron":3k3bxhc5 said:
1.5 rocker ratio=.470" lift
1.6 rocker ratio=.500" lift
1.65 rocker ratio=.516" lift
I hope you ordered the valve springs needed with that cam?
Since you are building a 250, you should have them grind the cam with a 4 degree advance. Reason is the timing chain is not adjustable on the 250 engine. The 200 you can use the AP set which is adjustable.
The stock Ford springs will not handle that cam. Bill