|10-16-2012 06:32 AM|
|TheRacerrick||With your compression a custom comp cam on a steel core with extreme marine lobes 3733 for exhaust 3475 for intake ground 112 +4 Use lunati 75820 beehive springs set them .060 from coil bind it won't float till 6500|
|10-14-2012 06:43 PM|
Information I found is,The oval port heads flow 270 cfm in the intake side and 190 cfm on the exhaust side,Thats 70% on the exhaust side so a split pattern camshaft would be needed.If you really know your engines you could make 590 horse power or probably a lot less with all the right parts.Thats using a .600 lift cam.
the peanut ports flow 225/160 for the 156 heads and 235/150-165 for the 236 peanut heads,so 450 horse power maybe,,,not worth using in a performance car.
|10-14-2012 02:24 PM|
The 781 heads are 700hp capable in full ported form with big valves. Suerstock super gas combo. (big racey roller 14:1cr)
They need some porting and the big valves for your motor. The valve job is critical for power on these heads. They make amazing power and torque on street motors just like this, using one of the many cams I suggested. ALl these will work very very well.
Follow my recomendations easy 550+hp and a ton of torque. with the solid flat tappets, more with the mech street rollers.
Big reliable power on nitrous that does not crap out before the end of the track
The hyd will.
I just went thru this with a friend here on his pro street 396 chevelle with nitrous.
He loves his new XR286R-10 mech street roller cam and K kit. . And has seen the light. The motor really hauls the freight now.
BBC's work way better with a mechanical cam. ALl the fast OEM hi perf muscle car BB's Chev Ford chrysler ran solid lifter cams. for a very good reason.
Hyd rollers are fine for 5500 rpm or less.
How far down the track do you want to get.?
|10-14-2012 01:36 PM|
781s /peanut heads/vic junior aluminum,???w/e head you use,doesnt matter,flow test them to see what power you can make,,,,other wise you are guessing.The number 500 is just a number for bench racing.lots of lower h p cars,,,IE honda,, or other little 4 bangers go faster than BB chevys for a reason.
RPM/gear matching,,weight/hookup,,,are the things you need to consider.
again,my 80 Camaro ran 11.9 with stock LS-5 specs,using z-55 cam,830 holley,vic oval port,hooker street headers,turbo 400, 219/188s. If you want to go faster,improve on that package,better heads would make the biggest difference.
|10-14-2012 01:20 PM|
Read my post #11 again and research the flat tappet alternatives.
Once of the best choices for a high quality flat tappet cam for your BBC.
ISKY Racing Cams - Do It Right. Race with the Legend. Camshafts, Connecting Rods, Valve Springs, Lifters
I have never seen a Isky flat tappet cam fail or wear out. solid or Hyd BBC or SBC ---Ever.
Their solid flat tappet BBC street cams rock.
Call 'em for cam choice help. Do no just shop the Isky catalog. call them.
something like their intake lobe # S-550 combined with exhaust lobe S-385 on a 110LSA, in on a 104 to 106 In C/L will rock.
278-288 244--254@.050 .595-.595" lift .016 .018 lash.
Now you're cooking with gas!
|10-14-2012 01:05 PM|
|F-BIRD'88||I have run BBC's for years. Lost one flat tappet cam in a BBC , after many years many miles of service. 7000rpm. just plain wore it out. Use quality stuff and you won't have problems.|
|10-14-2012 01:04 PM|
[QUOTE=F-BIRD'88;1599050]The K-11-770-8 and K11-771-8 kit is $900.
900 plus tax is $1000 in my books wich is not in my budget , Like I stated I can buy a hyd roller or replace the comp 274 with something else or run the 274 flat tappet , I plan on doing alot of street driving and the odd race track pass
|10-14-2012 12:56 PM|
|10-14-2012 12:49 PM|
Unless you put your peanut heads on a flow bench,you really have no idea how many horses you can get from your engine.Porting your peanut heads is not money well spent.You mentioned using 3.73 gears,so you need lower rpm/torque engine.If you use a big cam to make high rpm horse power then your peanut heads will hold you back.
when you have flow numbers you can determine HP potential,,,
|10-14-2012 12:49 PM|
Couple real nice street flat tappets
Lunati (UD Harold design. Ultradyne)
These will rock in your 454 truck with a bit of spray.
I believe the good UD Harold stuff is available thu Howards and Bullet cams too.
easy street manors great power and rpm.
Do it your way and spend more and come up short.
Then do it again.....
or do it right then first time ... once.
Your choice bud..
|10-14-2012 12:42 PM|
|jumbo2||XR mechanical K kit if over a grand , that doesnt sound to cost efective to me ?|
|10-14-2012 12:39 PM|
|10-14-2012 12:33 PM|
|10-14-2012 12:33 PM|
You next best low budget choie is a good BBC mechanical flat tappet cam and lifters.
They work real good too.
The BBC street hyd rollers tend to give up the ghost at 5500ish rpm some as soon as 5200
some 5800. most all al giveing up power by 6000rpm.
You do not want that with nitrous. The new improved limited plunger travel hyd roller lifters Crane etc.
are pricey and require a real good cam lobe design (Crane Hyd roller) and big springs.
now you are into money.
a lot of people that have been down this road end up running a solid mechanical roller lifter and more spring
on their Hyd roller cam to get the nessessary rpm capability . (very small cold lash setting .001" to .004")
Why not get get the right mechanical street roller cam and mechanical roller lifters in the first place?
Do you got enough money to do this twice- three times?
The mech street roller is the good deal ..... net cost and far superior performance in a BBC.
The XR mechanical street roller K kits are hard to beat.
|10-14-2012 12:09 PM|
The K kits are a great value. And well worth the price.
call comp cams for help.
The Howards mechanical street rollers are very good too.
keep the duration short and snotty 237 to 244 @.050"
Save another pay check or buy the hyd roller lifters and sell them to raise money.
to get the right cam for your BBC.
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