# 461 stroker stalls in gear



## Norms68 (Jul 17, 2013)

Hey guys,

Finished up the 461 stroker engine build. Tuned the carb but it stalls when I put it in reverse or drive. Here's the info:

1971 Pontiac 400 block stroked to 461. Comp Cams hyd roller 282/288 @ .050 230/236 .510/.521 112 lobe separation. 1.52 roller rockers. Edelbrock 87cc heads port matched performer RPM intake. 10.5:1 compression. Holley 4150 double pumper 800cfm with 110gph Holley mechanical fuel pump. MSD ready to run distributor, 8.5mm accel wires and NGK gapped to .045. TCI 11" 2400-2600 stall converter. TH400 Auto.

Initial timing set at 17 and total at 38 all in about 2800 rpm. Electric choke set at about 1600 rpm. Floats set to bottom of sight screw. Idle screws set at 1 and 1/2 turns out then checked vacuum. Turned idle screw 1/4 turn in on both sides and got little better vacuum at 15. Tried another 1/4 turn and vacuum dropped off. Turned back 1/4 turn and sits at 15 again. So total of 1 and 1/4 turns from fully seated. Turned curb idle for 1000 rpm expecting 800 in gear. I think this new carb comes with 7.5 power valve so that should be perfect.

As I put in gear it stalls out. Didn't expect this because everything looks by the book. Also took carb off and checked transfer slots, got the .020 square...

Too much advance?

Thanks for any help.
-Norm


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## PontiacJim (Dec 29, 2012)

Read this blog as it may be helpful to you: 4160 Holley idle problems Page1 - High Performance Pontiac Forums at Hot Rod Magazine Magazine

Here is another one, read " setting idle speed" at the bottom of the page:Almost Everything You Would Want to Know about Holley Carburetors - Car Craft Magazine

These are suggestions to look into. I am no expert on Holley's and have never run one as I always went with the Q-jet on Pontiacs. You may want to try raising your idle up to 1,200 RPM's with that cam just to see if that works. Could be your combination may need a higher RPM range when you drop it in gear. Not saying this is it, but sometimes bigger cams do need more RPM's at idle or they will stall -and if you have a "tight" torque converter this can aggravate the situation as opposed to a "loose" converter.


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## Bensjammin66 (May 12, 2009)

Sounds like the idle bleeds are set right. Any vacuum leaks? Get the ol' starting fluid out and check for an intake or carb vacuum leak. Pretty sure that would create the problems you are seeing, stalling under a load. What happens with say a 1300rpm idle in park, when you drop it in gear it still stalls?


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## Norms68 (Jul 17, 2013)

Found the culprit. Was missing.

I failed to check the coil voltage with key in START position. I checked it in ACC position and got 12v thinking it was good wire. Rechecked it in START position and saw it dropped to 9v. My MSD ready-to-run needs 12v.

Alligator clipped 12v directly to coil and she purs like a kitten... I mean lion, its a 461 after all. Just have to cut out that resisted wire and rewire it.

-Norm


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## Bensjammin66 (May 12, 2009)

Outstanding news. Glad to hear its running! Spring is here!


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## BearGFR (Aug 25, 2008)

If you don't want to mess with re-wiring your ignition circuit, do what I did. Get yourself a generic headlight relay, mount it to the firewall, then use your original ignition circuit to trigger the relay (the "other" side of which should be wired to supply a full 12v to your ignition). Nothing to cut, nothing to rewire, and if you eve decide you want to go back to 'original' it's simple.

Bear


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## Norms68 (Jul 17, 2013)

Good deal thanks.

I ended up having a 12-14v relay so I used an alternate 12v acc source to power a lead direct from the battery positive. Works great.

-Norm


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## cal kid (Dec 19, 2018)

Hi Norm, I am getting my parts together for a 461 build much like yours and I am concearned about my compression ratio on the crappy 91 octane gas here in Calif. what are you using for pistons and did your machinist zero deck the block? Thanks Randy


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## BearGFR (Aug 25, 2008)

cal kid said:


> Hi Norm, I am getting my parts together for a 461 build much like yours and I am concearned about my compression ratio on the crappy 91 octane gas here in Calif. what are you using for pistons and did your machinist zero deck the block? Thanks Randy


Hey Randy,

Generally speaking the 'rule of thumb' with iron heads is to try to set your compression ratio to "about" (octane rating)/10. So, for 91 octane fuel with iron heads, you'd want to shoot for 9.1:1. 
If you're going to run cast iron heads, it's a different proposition from running aftermarket aluminum heads. Aluminum heads can tolerate (and actually need) more compression than iron. 
With aluminum you could probably get away with 10.1:1.

Note that this is a general recommendation, not an inviolate hard and fast rule, because there can be many other factors that have an influence such as cam timing/duration, altitude, deck height, combustion chamber shape, etc. 

Some people can and do get away with "more" on occasion, but being successful at it is dependent on all those other factors so you kinda have to know what you're doing. Otherwise, you're sort of taking a risk.

Also keep in mind, that on a street engine _with no other changes,_ the difference in power output between 9:1 and 10:1 will only amount to less that 10 HP so for most folks it's really not worth the risk to try to push compression to the limit.

Cheers,
Bear


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## cal kid (Dec 19, 2018)

Hi Bear, Thanks for your comments, like most novices I don't want to pick the wrong parts !
Things that I know.. 
Home is sea level in Ca. with only 91 octane pump gas available.
My mom drove the 72 Lemans sport convert home from the dealer my senior year, fast forward 50 years, it now has 150K Mi. on the clock and still runs fine with the heads never being off.
I have ordered but not shipped yet KRE 85 CC D-ports bare heads.
Ordered 461 all forged Ohio stroker kit from KRE w/ 4.155 Ross flat top pistons w/ 6.8 rods
Ordered but not shipped yet, RARE RM-2-0S 2 1/2 thermal coated manifolds w/ 2 1/2 down pipe.
I have an Art Carr built TH2004r w/ 2400 stall converter, Torsen T2r 3.70 9in w/ Wilwoods all around to wo it up. : ) Edelbrock Performer RPM manifold
275/60R15 BFG T/A's out back. Thanks Randy

PS many parts and things I don't know about : ( Like Compression Ratios


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## BearGFR (Aug 25, 2008)

Ok, so aluminum heads. Good choice. Also congrats for ordering them bare. You'll get much better quality by doing that and having them finished out by a good builder. So... 85 CC's, flat top Pistons (which usually have about 6cc's in the valve pockets). 

I have an Excel sheet I built that makes all the calculations. 

On a 461 (4.25 stroke by 4.155 bore) with everything else being "nominal", that puts you at 10.15:1 if I assume the Pontiac usual 0.011 deck clearance. With aluminum heads on 91 octane, I'd be comfortable with that. If you zero-deck the block, then it'll be 10.37:1. That still might be ok depending on cam duration/timing but less certain than 10.15:1. 

I'm in Texas at a slightly higher elevation, I run 93 octane in my 461, and it's fine at 10.5:1, but I run a "moderately rowdy" solid roller cam in it.

Sounds like you're on your way to a really nice build. 

Bear


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## cal kid (Dec 19, 2018)

Hi Bear,
I spoke with Jeff from Kaufman Racing and he said that the Ross flat top pistons that he was suppling had 8 cc's valve pockets and if the heads had never been off the 400 and we were not going to surface the block the pistons would be ".015 down the hole". Does this sound correct ? I also have no clue what total quench is, but I saw that you recommended to shoot for between .040 to .045, what is quench and how it acchived ? Also is there any "meat" in the 85 CC combustion chamber on the KRE D-ports should we need to decrease the C R ? I beleve my target C R is 9.75 to 1. Also what is the gasket bore diameter on a 4.155 ?

Thanks Randy


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## BearGFR (Aug 25, 2008)

That's sounds reasonable, yes.


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## cal kid (Dec 19, 2018)

Great, thanks for posting. Randy


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