Another 416 Stroker Build-Pic Heavy

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PRH said:
What did the final flow numbers look like?
And, what are the cams specs?

240 psi...... I wouldn’t be brave enough to try and run that on straight pump gas.

The current headers are 1-3/4x3?
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They are small Hedman 1 5/8 truck headers. I said I was going to try straight av gas not the current 25% pump 75% av gas.
Flow numbers are what they were earlier in this thread 260-265 at most. Cam is a reground comp roller, 254/260 . The report is also in this thread. J.Rob
 
those numbers are very impressive for factory production heads and a tight engine . it will be interesting to see what the straight 100 LL will do .
 
Flow numbers are what they were earlier in this thread 260-265 at most. Cam is a reground comp roller, 254/260 . The report is also in this thread.
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Thanks.
I just figured it would be nice to recap a few of the highlights near the results.

I’m sure those headers are costing you some upper rpm power.
 
PRH said:
Thanks.
I just figured it would be nice to recap a few of the highlights near the results.

I’m sure those headers are costing you some upper rpm power.
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I'm not so sure, I hate the x head exhaust port shape. Really hoping to try the bigger ttis. J.Rob
 
jimjimjimmy said:
those numbers are very impressive for factory production heads and a tight engine . it will be interesting to see what the straight 100 LL will do .
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I don t anticipate a big difference with straight avgas, but I did find it odd that I could barely smell it when I was trying to figure out the stuck secondary float and no pump shot front or back!. You wouldn't believe what I found. I figured it would be a little stronger than this but then again this is the most power I've made out of old x/j/'596, .....etc.... pre magnums. J.Rob
 
How much air is it using?
VE?

Any bigger shop carbs on hand that might not be as rich?
 
I figured it would be a little stronger than this but then again this is the most power I've made out of old x/j/'596
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What kind of difference would you expect to see if you just swapped the heads for some very similar flowing RPM heads, assuming the CR stayed the same?
 
PRH said:
What kind of difference would you expect to see if you just swapped the heads for some very similar flowing RPM heads, assuming the CR stayed the same?
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I have a some other 408-416 to compare to on file. O ne that comes to mind with Edelbrock ported by another shop with pushrods tubed made 470 ish hp but lower compression and flat tappet cam and Airway. Oh and they were the Magnum Edelbrocks. I will look some past builds up. J.Rob
 
There was a 410 on the dyno here a couple years ago.
10.5cr, blended RPM heads(265-270), similar sized SR cam with very easy on parts lobes(251/259-108), regular Victor intake, QFT 850, 1-5/8 to 1-3/4 x 3 headers.
I wasnt the one who ran it, and the sheet I got for it has the carb way way fat(a/f in the 11’s and even some 10’s), bsfc are horrible.
Where you ended your pull(5800), that motor wasn’t using much more air than you saw......637cfm.
VE at peak TQ is about the same......
102-103%.

The tq curve wasn’t nearly as strong or flat as your build, but it hung on long enough to make a little more hp....... so far.
 
RAMM said:
I don t anticipate a big difference with straight avgas, but I did find it odd that I could barely smell it when I was trying to figure out the stuck secondary float and no pump shot front or back!. You wouldn't believe what I found. I figured it would be a little stronger than this but then again this is the most power I've made out of old x/j/'596, .....etc.... pre magnums. J.Rob
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Not a knock, but that's telling.
This experience with these heads i think was good for you. We all enter this hobby through different doors/levels. The x exh port is particular with shape and the j follows the same.
Thanks for sharing.
 
It'll be interesting to see what the headers do. I generally think people over-tube headers. Of course.... a well designed set of over-tubed headers will be better than a crummy set of properly-tubed headers.

For me....the hot rod stuff has reached the point where I can hardly stand to use a carb at all, but I sure hate the cost of EFI.
 
MOPAROFFICIAL said:
Not a knock, but that's telling.
This experience with these heads i think was good for you. We all enter this hobby through different doors/levels. The x exh port is particular with shape and the j follows the same.
Thanks for sharing.
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Lol, What it tells me is that I've never had a customer willing to pay me to work this type of head to this extent. Didnt hardly touch the exhaust ports with their gawd awful shape as is. I also figured this would hit the 500hp goal the customer mandated. J.Rob
 
Interested to see what your header change does. When I switched from 1-5/8 to TTI stepped headers on a 600 hp engine we gained an average of 1 hp from 3,000-6,000 rpm and after 6,000 the power went up......seemed like 10 hp if I remember correctly.

Your adventure is keeping me smiling. I like it.
 
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IQ52 said:
Interested to see what your header change does. When I switched from 1-5/8 to TTI stepped headers on a 600 hp engine we gained an average of 1 hp from 3,000-6,000 rpm and after 6,000 the power went up......seemed like 10 hp if I remember correctly.

Your adventure is keeping me smiling. I like it.
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I'm thinking the tube size isn't going to make a noticeable difference at this output level, in fact I bet it loses TQ just about everywhere. Glad you are smiling Jim. I came in today and lashed the valves .002" tighter and looked at how much fuel the rear bowl was moving and decided 82's and a plugged P.V. was too much so in went a pair of 78's. I also set timing back @ 35 from 37 and now I'm going backwards with about a 7 hp loss. I know I know 3 changes at once.... Waiting for the headers at the moment. Checked the S.G. of the fuel and it came in at .712. I think its going to be one of those days. J.Rob

SGFuel.jpg
 
those are good numbers for what you have stock heads small headers . I'm hoping my 426 will have numbers like that , maybe 30 hp more running a mix of 112 octane and 94
 
Ok so I had my friend GB who is a true carb guru come in with his tried and true 750 downleg with a Holley HP main body. We knew it was going to be good the way it sounded while bringing it up to temp. Did 4 pulls jetting up the carb once. Amazing what a straightened out carb will do. Very pleased with how this turned out. Oh and the customer is way too busy with work to get the TTI's in so thats it for this one. I have 3 other engines waiting in line for the dyno. J.Rob

Finalpull750DL.jpg


750ANNvs750DL.jpg
 
wow it made more hp and tq than my 418 with porterd rpm's your customer will be very pleased .
 
RAMM said:
Check how even bank to bank is with the 750 DL carb. Way better. J.Rob

View attachment 1715655903
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Some day someone will tell my why an annular booster in anything except a dominator is a good thing. I’ve never seen it work.

The customer should be at least as happy as a pig in poo with that engine. Notwithstanding the one piece crank.
 
You might tell me different cuz you run the dyno, but 10HP on a 500HP engine is 2%. I'd consider that 'insignificant' as it probably is right around the accuracy level of the meters, sensors, and dyno itself. Right or wrong?
 
:thumbsup:
That’s more like it.
The bsfc numbers look really good with that carb.

The two dyno curves really tell the story.
 
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