Another New Engine Ready for the Dyno

[lars]

Just finished building up another small block, and it's going on the dyno, as usual... This time it's a little 383, based on a stock-block 350 with an Eagle crank, 6" H-Beam rods, JE pistons, Pro-Topline heads, CompCams hydraulic roller and a BG Demon 750 mechanical secondary carb. On the dyno, we're going to run it with and without a 1" carb spacer, and we're running a set of 1-5/8" headers along with a set of 1-3/4" headers to see the difference in a street motor. We'll do the usual timing and jetting optimization, of course, and give it a good flogging before the motor goes into a Vette. Here's the engine ready to load and transport... anyone care to guess at the power/torque numbers we'll get...?

The last engine was just a little bit bigger and had a solid roller, single plane intake, and some big-tube headers. Numbers were 496/500:

 

[lars]

No takers on the numbers guess, eh?

Here's my guess: 420hp/440 lb/ft. It's a pretty mild engine, and it idles smoothly at 700 rpm... But I'm thinking that torque will be all-in at about 3500 rpm, making this a fantastic street engine. Let's see how far off I am...

 

[Mac]

How has your luck been with the Pro Topline heads? I've read there's been problems with their valve seats.

Mild stroker, hydro-roller cam, looks like a dual plane intake... I'm going to guess 380hp and 400 lb/ft.

-Mac

 

[lars]

How has your luck been with the Pro Topline heads? I've read there's been problems with their valve seats.

That was back when the heads were built in New Zealand under the original Pro Topline label. They're now machined and assembled in the US under the RHS (Racing Head Service) brand and sold by CompCams - the quality issues have been resolved, and the heads are very good. I've installed them on quite a few engines now, with excellent results and reliability. The iron heads make a litle more power than the aluminum heads if installed on the same engine without changing compression ratio.

I'm going to guess 380hp and 400 lb/ft.
-Mac

Less than 1hp/ci... hmmmm.... I'll be sure to post up the results of the different combination runs under a dedicated thread. I hope I do better than 1:1...

So here is the guess tally:

Mac: 380/400
Lars: 420/440
Rowdy1: 430/440
Herminator: 440/440
rgtrough: 453/465 & 460/451 ft

Dyno run is scheduled for 8am Friday 2/18/11...

 

[Rowdy1]

Ok........

What do I win? My $.02 430 HP 440+ ft/lb

 

[lars]

What do I win? My $.02 430 HP 440+ ft/lb

Honor, glamour, and hearty slaps on the back...

 

[herminator]

Guessing 440 hp, 440+ lbs. Please advise differences found in the two different header sizes, I am also very interested in that.

 

[rgtrough]

With out the cam numbers this is truly a guess but put me down for 453 hp and 465 ft lb with 1 5/8". 460 hp and 451 ft lb with 1 3/4" headers

 

[RealmSteel]

I have no guess on numbers, just interested in the spacer and header size changes.

It's been a long time since I built SBC and then I never put anything on a dyno, just the street. Wish I had the access and money to though back then.

 

[lars]

I'll be sure to post up photos of the run as well as numbers achieved from each combination. The back-to-back header size comparision and the spacer runs should be interesting. The spacer/header changes may require some jetting changes to keep the A/F ratio optimum. I'll nail down the best total timing first (I'm guessing it will be between 32 and 34 with these heads) and then set it up for best tuned configuration (jetting) with no spacer and the small headers. I'll then add the spacer, re-set A/F if needed, and finally go with the big headers along with any needed jet change. If time allows, I'll pull the spacer out and leave the big headers on it for a final pull (which would be good to know, since the spacer won't fit under the Vette hood without a hood change).

The dyno I use prints out the numbers, but no fancy graphs. To get a graph, I have to input all the numbers into an excel spreadsheet, so I may just post up peak numbers with my observations on what the overall curve did.

Keep the guesses coming and I'll arrange them in my post above. I'll post up the dyno results Friday afternoon or Saturday morning in a new topic thread so everyone can see when it's up... I'll also post up the entire engine combo (and cam specs) at that time. Until then, it's classified...:L

Here's a photo of another engine I built for some happy Vette owners (pictured in background): The small block just pulled off a 530 hp run with 528 ft/lbs torque, all under 6000 rpm with a hydraulic cam (engine was pulling 440 ft/lbs at the 2500 rpm start on the pulls). And it idles at 900 rpm...

 

[Rowdy1]

I'm Thinking.............

I'll be sure to post up photos of the run as well as numbers achieved from each combination. The back-to-back header size comparision and the spacer runs should be interesting. The spacer/header changes may require some jetting changes to keep the A/F ratio optimum. I'll nail down the best total timing first (I'm guessing it will be between 32 and 34 with these heads) and then set it up for best tuned configuration (jetting) with no spacer and the small headers. I'll then add the spacer, re-set A/F if needed, and finally go with the big headers along with any needed jet change. If time allows, I'll pull the spacer out and leave the big headers on it for a final pull (which would be good to know, since the spacer won't fit under the Vette hood without a hood change).

The dyno I use prints out the numbers, but no fancy graphs. To get a graph, I have to input all the numbers into an excel spreadsheet, so I may just post up peak numbers with my observations on what the overall curve did.

Keep the guesses coming and I'll arrange them in my post above. I'll post up the dyno results Friday afternoon or Saturday morning in a new topic thread so everyone can see when it's up... I'll also post up the entire engine combo (and cam specs) at that time. Until then, it's classified...:L

Here's a photo of another engine I built for some happy Vette owners (pictured in background): The small block just pulled off a 530 hp run with 528 ft/lbs torque, all under 6000 rpm with a hydraulic cam (engine was pulling 440 ft/lbs at the 2500 rpm start on the pulls). And it idles at 900 rpm...

I may want to change my #'s. Now you went and threw a curve in the mix with this post. I'll never find the new post, hell, I may never know if I was right

 

[Mac]

I'm fairly old-school, Lars. My experience with hydraulic roller cams is limited. I know they've advanced but unsure how aggressive of a profile you can push them.

Glad to hear the Pro Topline heads improved. If memory serves, they've been associated with CompCams, even when they were problematic.

-Mac

 

[lars]

I may want to change my #'s. Now you went and threw a curve in the mix with this post. I'll never find the new post, hell, I may never know if I was right

I'll make sure you know about the post, even if I have to send you a note or come pound on your door (gawd, this Forum is so slow that if you check in once a week you'll see the latest post still at the top of the list...)

Lars

 

[Rowdy1]

Thanks

I'll make sure you know about the post, even if I have to send you a note or come pound on your door (gawd, this Forum is so slow that if you check in once a week you'll see the latest post still at the top of the list...)

Lars

If Ya pound on the door, use the garage door, I don't spend much time in the house. Oh yeah, bring

 

[lars]

You must think I sit in the house watching 2-1/2 Men in my spare time... If you don't pound on my garage door or come in the back door, you won't get any response from me, either. I never thought to knock on your front door... I wouldn't be coming over to visit your wife. I was going to pound on the garage door or come in the side door to the garage. I never knew there was any other entrance to a real guy's house...
Dont' worry, I always bring the

 

[Rowdy1]

Nope.......

You must think I sit in the house watching 2-1/2 Men in my spare time... If you don't pound on my garage door or come in the back door, you won't get any response from me, either. I never thought to knock on your front door... I wouldn't be coming over to visit your wife. I was going to pound on the garage door or come in the side door to the garage. I never knew there was any other entrance to a real guy's house...
Dont' worry, I always bring the

I don't need no stinking TV, just the dyno #'s and the . Your avatar looks like me in between rounds at the track waiting for them to clean up after an oil down

 

[rgtrough]

I'll be interested to compare your results with mine. We have very similar componets. I used AFR 195 heads with a comp cams hyd. roller. 34 degrees is where mine was the most productive.

 

[lars]

Results of the dyno testing can be found in the post, "383 Dyno Results."

Click here:

http://www.corvetteactioncenter.com...ance/125743-383-dyno-results.html#post1060420

Lars

 

[RealmSteel]

Thanks for the info.
Don't know when the next time I'll build another engine, but I'll pack this info away 'til then.

 

[Rowdy1]

Good Job...........

Results of the dyno testing can be found in the post, "383 Dyno Results."

Click here:

http://www.corvetteactioncenter.com...ance/125743-383-dyno-results.html#post1060420

Lars

By both of us, I don't feel too bad coming in 2nd to the builder