![]() |
My question too is what's the point in 7K? I use my Roush 427SR for track days, but see no point in anything over 6200rpm. The Roush dyno sheet shows max hp at 5700 rpm and max torque at 4400 rpm. Plenty of power shifting at 6200. Beyond that power drops off anyway. You want high reving engines, get a 4 cylinder with a really wild cam and a power band 8-10K rpm.
|
my v8 now revs to 7500rpm with power all the way to redline, i just want the ssame felling with lots of tq, i understand high rpm less streetable and vise versa, i want the perfect medium of tq and rpm, thanks for the info. (by the way i would never buy a roush, there made in mexico for cheap labor and none of the savings is passed on to the consumer, ill take my blykins USA build for cheaper with better parts.)
|
With perfectly tuned EFI and variable cam timing, you can get away with a lot more on the street.
However, for the old school pushrod V8, there are plenty of ways of getting a "happy medium" powerband for street and racing. I like the revvy engines myself, but you have to put a cap on that somewhere if you want something that's not a pain in the butt on the street. For a "peppy street" engine, I like the hp peak to be somewhere between 6000-6500. This still allows a nice torque curve and doesn't require a camshaft that is uber-fussy down low. |
6500 sounds perfect, thanks for all the advice, im getting excited about this for my next project
|
If I want torque at a lower rpm, I take my truck-----it'll do 3000rpm all day---and nite!!!
|
Quote:
|
thanks brett, thats what i was trying to say, 6000-6500 with power up to that level with a streetabe cam, just dont want power to fall off at 5500 range.
|
nope
Quote:
|
fms catalog has a 374 late model engine listed with a daley dry sump and all the goodies, be a good revving type engine if you had the cash.
|
Quote:
Second, Roush is in Livonia, MI. On a map you can clearly see that is in fact in the USA. That is where the engines are assembled and tested. The parts used are sourced from the USA to the extent that parts today can be. |
It's nice when you fill in some of the answers
fordracing 65 You have a problem, nothing that 20K willnot help fix. If you want a torque motor that will rip the tires of the rims, thats great. The only problem is having a 6,500 limit with the HP topping out at 6,500. Big bore short stroke motor is not going to give you both. You will have a large rpm range with the correct valve train and camshaft.
You have not said what oiling system you are looking at? The FI system is great, but which one has your eye? 8 stacks or 2,000 cfm throttlebody? With 427 cubes and 6,500rpm, a set of 48 mm throttle body will be at there flow limits. Camshaft is also very important for FI to work correctly. Something in the 112LSA to 114LSA min for your motor. Something in the .600- .650 lift is about max for a street driving motor to live and not have to replace valve springs every 10,000 miles or less. What heads are you looking at? Clevor heads might be a good choice if you have the bottom of the ports filled in on the intake and chance of the exhaust to more of a "D" port with flat being on the bottom. Porting and matching the intake and heads will come into play. Joe Craine does one of the best jobs of matching each port on the intake to flow within 3-5 cfm of each port. This will help balance the flow to the motor. Just something to think about too. Rick l. |
Awesome info thanks, so many ways to skin a cat i guess.
|
Torque and RPM,
Sounds like a big bore, short stroke alum big block is what you really need! lol :MECOOL: Jason |
Nothing like a de-stroked BB!
|
Just ordered my parts would love to get advice from blykins and other engine builders on this sight, Dart sportsman block, Scat 4340 forged crank, Scat 4340 forged H beam rods, JE superlight pistons, hand fitted Plasma moly/iron ductile rings, Clevite H series main and rod bearings, hydraulic roller cam with lightweight transfer bar roller lifters, a double roller timing assembly, chrome moly push rods, Fel Pro regular gaskets, MLS head gaskets, APR head bolts, CNC'd AFR 227 heads, ported matched Victor series intake manifold, T&D shaft rockers, polished aluminium valve covers with billet breathers, new timing chain cover, a polished SFI harmonic balancer, ARP harmonic balancer bolt, SFI flex plate, a fully balanced(within 1/4 gram) rotating assembly, Mass-flow EFI system with an msd pro billet distributor, spark plugs, 8 quart Milodon oil pan & pickup, stainless steel allen bolts, Edelbrock high flow water pump, Chrome 1 wire alternator, March billet alternator bracket, March billet serpentine pulleys, Chrome dip stick.
Should take me a few months to put together then dyno i will post results then, thanks for any advice. |
Everything looks good except for the hydraulic roller....
For the rpms you're wanting to spin, I'd bypass the hydraulic stuff altogether. Too much risk and liability when the valves float... |
427w
My 351w is a 9.2 deck Dart alloy block 4.125 bore 373 cuin, 6.2" carrillos, Yates heads, engine custom built by Keith Craft runs on premium pump gas, 8000 rpm at 675bhp.
When I received the engine we dynoed it and decided to change the inlet manifold due to epoxy in the runners and NZ pump fuel compatibility, I purchased a small port 2960 edelbrock manifold to replace the balls out job, Lost (1bhp) at 7000rpm and gained 25bhp at 4000rpm plus lowered the peak torque by 500rpm down to 5000rpm. There is no point now in going over 7000rpm and even at 6000rpm I have over 600bhp. There was quite a bit of work to port match the new manifold, and I had to cut the valley plate out as I wanted to keep the removable Penske valley cover, so I can change cam lifters etc. I would imagine when I am road racing there will be no need to go over 6500rpm, it will be more important to get the car handling to put all this power down. |
Why rev the guts out of your bank balance when you dont have to?
|
dont need to rev high just want pull all the way to redline at 6500rpm, thanks for all the info.
|
What's the cam specs?
If you're going to try and stay hydraulic, I'd ditch the link bar lifters, then run as light of valvetrain as you can....titanium retainers, locks, lightened lifters, etc. I absolutely hate hydraulic cams for higher rpms. You can make them live at higher rpms, but it takes a little extra effort. For anything over 6000, I'd rather have a solid cam. |
| All times are GMT -7. The time now is 04:04 PM. |
Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2026, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0
The representations expressed are the representations and opinions of the clubcobra.com forum members and do not necessarily reflect the opinions and viewpoints of the site owners, moderators, Shelby American, any other replica manufacturer, Ford Motor Company. This website has been planned and developed by clubcobra.com and its forum members and should not be construed as being endorsed by Ford Motor Company, or Shelby American or any other manufacturer unless expressly noted by that entity. "Cobra" and the Cobra logo are registered trademarks for Ford Motor Co., Inc. clubcobra.com forum members agree not to post any copyrighted material unless the copyrighted material is owned by you. Although we do not and cannot review the messages posted and are not responsible for the content of any of these messages, we reserve the right to delete any message for any reason whatsoever. You remain solely responsible for the content of your messages, and you agree to indemnify and hold us harmless with respect to any claim based upon transmission of your message(s). Thank you for visiting clubcobra.com. For full policy documentation refer to the following link: