opinions welcome on build.

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I will take a big bore short stroke with a good flowing cylinder head every time. 4.250 at a minimum !
 
I think most people especially ones who are mainly street don't want to gear more than 3.55 and want 450-550 hp should go 408 or to me big block.
But if your willing to gear it love rpm and a race car idle no reason why you can't just spin a stock stroke up to those power levels.
Really just depends on the person and situation. I'd rather gear and spin it but that's me plus I do believe there is an advantage with 3.31/3.58 strokes biggest I'd go is 3.79.
 
Thank you ALL for the replys, has turned into a good, thought provoking thread. Again, car will be a cruiser, and see time at 1/4 mile strip. Must drive to and hopefully from. Originally was keeping 3.31 stroke, drag cam and 850/950 hp carb. I now want and am using e.f.i, therefore the 106-108 l.s.a cams are out. (need 9-10" of vacuum) still will be big lift 240ish duration i hope. Will be custom. The heads have long valves etc: So, as stated, am going to add stroke. The 4" stuff looks easy and reasonable. Not seeing a lot of 3.79" stuff, or matching 6.250" rods with 4.00" stroke, 4.070" bore pistons. I posted on 318 cams thread. I will be using a 8 3/4, 3.91 suregrip i bought. Again, thanks to everybody!!
 
mechanicmark said:
Thank you ALL for the replys, has turned into a good, thought provoking thread. Again, car will be a cruiser, and see time at 1/4 mile strip. Must drive to and hopefully from. Originally was keeping 3.31 stroke, drag cam and 850/950 hp carb. I now want and am using e.f.i, therefore the 106-108 l.s.a cams are out. (need 9-10" of vacuum) still will be big lift 240ish duration i hope. Will be custom. The heads have long valves etc: So, as stated, am going to add stroke. The 4" stuff looks easy and reasonable. Not seeing a lot of 3.79" stuff, or matching 6.250" rods with 4.00" stroke, 4.070" bore pistons. I posted on 318 cams thread. I will be using a 8 3/4, 3.91 suregrip i bought. Again, thanks to everybody!!
Click to expand...


If you buy a custom cam, you will be far, far ahead. On 340 inches I run 255 at .050 on a 105 LSA installed at 105 and I get almost 10 inches of vacuum at an 800 RPM idle.

I would try and get all the power you can and opening the LSA for no reason other than to try and get idle vacuum up isn't one of them. You should be able to do that without compromising cam timing.
 
sorta agree with YR
LSA is a result not an input
figure the degrees of overlap at .004 or .006- whatever your cam grinder uses and use a number that gives you the vacuum you need
(obviously you have to take the durations into account when figuring overlap- lsa by itself is meaningless)
that covers intake open and exhaust close for a first check, now determine your intake close (as early as possible) and exhaust open (as late as possible)( at your rpm and power levels desired) and see where you're at
as you have noticed 4 " and even longer parts are easier to find and less $$ (except for the pistons) than 3.79- but shop around
get your head flows even .050
get the data together required to fill out both of these forms and everything else relevant
Road Race | Jones Cams
Street Performance | Jones Cams
if FT or Roller
 
yellow rose said:
If you buy a custom cam, you will be far, far ahead. On 340 inches I run 255 at .050 on a 105 LSA installed at 105 and I get almost 10 inches of vacuum at an 800 RPM idle.

I would try and get all the power you can and opening the LSA for no reason other than to try and get idle vacuum up isn't one of them. You should be able to do that without compromising cam timing.
Click to expand...
I would have never guessed that kind of vacuum with that cam, good to know. Mark.
 
Wyrmrider said:
sorta agree with YR
LSA is a result not an input
figure the degrees of overlap at .004 or .006- whatever your cam grinder uses and use a number that gives you the vacuum you need
(obviously you have to take the durations into account when figuring overlap- lsa by itself is meaningless)
that covers intake open and exhaust close for a first check, now determine your intake close (as early as possible) and exhaust open (as late as possible)( at your rpm and power levels desired) and see where you're at
as you have noticed 4 " and even longer parts are easier to find and less $$ (except for the pistons) than 3.79- but shop around
get your head flows even .050
get the data together required to fill out both of these forms and everything else relevant
Road Race | Jones Cams
Street Performance | Jones Cams
if FT or Roller
Click to expand...
Thanks, I will check them out. Mark.
 
send your specs to Mike Jones or use the Controlled Induction Software or another computer software to figure it out for you
the extra cost of a cam that way will really pay for itself unless YOU are very experienced
Our Crower rep could also help
everything else is folkwisdom (which is also ok with enough inputs)
 
My expectation of a 255/255-105 cam in a motor running thru closed exhaust and utilizing EFI is........if it’s a totally user configurable system(and someone very experienced is doing the tuning), it won’t be very fun trying to get it dialed in, and is likely always going to be quirky in some part of its operation.

And if it’s a sniper type of throttle body deal........ it just won’t that run well at low rpm, or driving at low speeds.

My advice would be, talk to whoever is going to help with the tuning and get some feedback on how they feel that cam will work with with your EFI system.

As always, ymmv.
 
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