SBC Horsepower estimate

General engine tech -- Drag Racing to Circle Track

Moderator: Team

MELWAY
Expert
Expert
Posts: 751
Joined: Mon Dec 04, 2006 7:37 pm
Location: melbourne australia

Re: SBC Horsepower estimate

Post by MELWAY » Mon Aug 14, 2017 8:39 pm

Sportsman 2 heads can be awesome on a 350-400" engine when ported right with correct valve job
I have made 650-670hp at 355 " and run 9.90@ 3400lb
So don't give up on your heads
450hp should be easy with right cam and a bit more compression
3370lb Sedan 9.89@136MPH 358chevN/A

lefty o
Pro
Pro
Posts: 390
Joined: Tue Oct 15, 2013 8:50 am

Re: SBC Horsepower estimate

Post by lefty o » Mon Aug 14, 2017 9:24 pm

ive got about a 20yr old build sitting in the garage. 355 with a fairly good ported set of sportsman II's, 9.8:1, old ultradyne flat solid cam if i recall correctly 250x262 .525" on a 106. with a holley strip dominator and a 750dp holley it made 474hp and 436ft lbs.its a tad rowdy, but i daily drove it one summer.

wilson1970
Member
Member
Posts: 53
Joined: Sun May 14, 2017 3:29 pm

Re: SBC Horsepower estimate

Post by wilson1970 » Tue Aug 15, 2017 5:28 pm

Does anyone have opinions on Hydraulic roller lifter brands? Is one better than another?

Kbails
Member
Member
Posts: 95
Joined: Sun Apr 05, 2015 6:53 pm

Re: SBC Horsepower estimate

Post by Kbails » Tue Aug 15, 2017 8:37 pm

I built a 400 .040 over last year with sportsman 2 heads that had a lot of attention ended up at 215cc 2.05-1.6 valve, 250-262 solid ft cam 10.5:1 comp made around 500 judging by the et. and weight it ran 11:70-80 thru th400 and 10 bolt 4:10 gear
You don't have to be great to start, but you have to start to be great.

6.50camaro
New Member
New Member
Posts: 14
Joined: Sun Jul 30, 2017 2:24 pm

Re: SBC Horsepower estimate

Post by 6.50camaro » Wed Aug 16, 2017 5:35 am

I used Cane can find no fault with them . Used them in two motors turned them up to 7k rpm no issues.

Monza355
Pro
Pro
Posts: 222
Joined: Sat Dec 07, 2013 6:06 pm

Re: SBC Horsepower estimate

Post by Monza355 » Thu Aug 17, 2017 9:31 am

I'm actually doing a very similar motor now. Hoping for 450 hp as well.

I have a 10:1 350 with ported sportsman heads. Ported victor jr intake and a 950 hp Holley. The cam is also 236/242 @.050" but a solid roller with 602/608" lift and 110 lsa.
I'm building this for decent street manners with good power and a 3500 stall converter.

Frankshaft
Pro
Pro
Posts: 426
Joined: Sun Jul 05, 2015 6:01 pm

Re: SBC Horsepower estimate

Post by Frankshaft » Thu Aug 17, 2017 9:47 am

I had a similar engine years ago for my 73 Camaro, 406, had rebuilt stock 5.565 rods with arp bolts, stock crank ground .010/.010, trw forged replacement dish pistons, it was about 9.5:1, sportsman 2's, bowl ported, elgin hyd flat tappet cam, 244/244 .510 lift on 108 lobe sep, victor jr intake for hood clearance, fit under my flat stock hood with a drop base air cleaner, nd a 3310 holley with choke horn milled off. Made just shy of 500hp and 488 ft/lbs. A perf rpm dual plane, it was a hair over 500 ft/lbs and lost about 10 peak hp, but wouldn't fit under my hood. It was a snappy, fun street engine.

greg
Member
Member
Posts: 190
Joined: Sun May 05, 2013 10:56 am

Re: SBC Horsepower estimate

Post by greg » Thu Aug 17, 2017 12:51 pm

why would anyone put or use steel heads,unless ur class require it

6.50camaro
New Member
New Member
Posts: 14
Joined: Sun Jul 30, 2017 2:24 pm

Re: SBC Horsepower estimate

Post by 6.50camaro » Thu Aug 17, 2017 2:35 pm

wilson1970 wrote:I know they arent stellar by any means. I bought these heads 20 years ago and at the time best that I could afford.
Had a .557 lift .256/.264@.050 flat tappet in it before. 9" converter with 4.10 gear. It ran really strong. Back in the day.
Because it is what he has. Just because there is something better on the market doesn't make what you have useless.

User avatar
psychomotors
Pro
Pro
Posts: 252
Joined: Sun Apr 27, 2014 8:20 pm
Location: East Bonne Terre
Contact:

Re: SBC Horsepower estimate

Post by psychomotors » Thu Aug 17, 2017 2:43 pm

6.50camaro wrote:
wilson1970 wrote:I know they arent stellar by any means. I bought these heads 20 years ago and at the time best that I could afford.
Had a .557 lift .256/.264@.050 flat tappet in it before. 9" converter with 4.10 gear. It ran really strong. Back in the day.
Because it is what he has. Just because there is something better on the market doesn't make what you have useless.
True story , especially when you don't have pockets full of money or sponsors ,lol. Curious as to why no one has asked what Lobe Separation for your cam.
Everyone appreciates your honesty , until you're honest with them , then you're an @$$hole.

wilson1970
Member
Member
Posts: 53
Joined: Sun May 14, 2017 3:29 pm

Re: SBC Horsepower estimate

Post by wilson1970 » Thu Aug 17, 2017 3:00 pm

I believe he wants to order a 112LSA .596 lift .236/242@.050. Possibly run a 1.6 rocker.

Frankshaft
Pro
Pro
Posts: 426
Joined: Sun Jul 05, 2015 6:01 pm

Re: SBC Horsepower estimate

Post by Frankshaft » Thu Aug 17, 2017 3:08 pm

greg wrote:why would anyone put or use steel heads,unless ur class require it
Hence my Rodney Dangerfield reference. Also, they are made from cast iron, not steel.

User avatar
MadBill
Guru
Guru
Posts: 12607
Joined: Tue Nov 15, 2005 10:41 am
Location: The Great White North

Re: SBC Horsepower estimate

Post by MadBill » Thu Aug 17, 2017 3:43 pm

Often overlooked fact: there's more iron in steel than there is in cast iron. #-o
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.

wilson1970
Member
Member
Posts: 53
Joined: Sun May 14, 2017 3:29 pm

Re: SBC Horsepower estimate

Post by wilson1970 » Sun Oct 22, 2017 1:24 pm

I decided to go with a .540 .236/.242@.050 will much power be lost in .060 in lift? Most likely will step up to a 1.6 Ratio rocker. This will give me .555 & .576 respectively

mag2555
Guru
Guru
Posts: 2062
Joined: Sun Sep 18, 2011 11:31 am

Re: SBC Horsepower estimate

Post by mag2555 » Mon Oct 23, 2017 6:53 am

The higher ratio is the way to go!
You will widen both the torque and Hp power band by some 250 to 300 rpm with no change in the rpm where they start off down low!
In a way it's better then running a somewhat bigger Cam!

Post Reply