71K5 - BP71K5's Just for fun build

[80' 427]

Those heads are fine for 4500-5000. I ran a 204/214 white box cam in my last super budget 454. With a qjet, weiand street warrior, 7.8 to 1 compression and headers/duals it made 336hp but 500ftlbs done at 3950. It idled dead smooth and rolled the 37s without a problem. My new attempt is for my 74 chevelle. Unknown history 79 454 out of a 85 c20. Added a 228/235 cam, same weiand intake, maybe 8-1 compression, 800 cam qjet, headers and duals. Idled at 800 with 15"of hg. It is getting a 2800-3000 stall and 3.23 posi. On a truck I would probably go 214/224 this time. The biggest problem with any factory efi is that it doesn't allow leaner part throttle crusing like all the preemissions carbs did. It should easily cruise at 15.5-16 to one and run cooler and get better mpg.

 

[Hoss7979]

When I measured them, they were pretty close to the smallest port in that diagram.

Pics of the intake runners?

Honestly I'm no longer sure of what I want. I'm leaning towards being able to take advantage of any "low hanging fruit" that exists for power while keeping my idle rock solid. Dont need to get it over 4500 RPM.

I'd like a decent cam that can get me more hp/torque without ruining the idle quality too much. Looking at a comp Xtreme 4x4, x4 262H at the moment.
Fuel injection is also a requirement.

If the heads I have need more than $500 in work, seems like more modern iron heads might be a decent option? That might not be the case though. I can get whatever intake is needed and am starting to think seriously about selling all my TBI burning equipment and parts and switching to the Holley TBI injection.

Not a bad option, I run the next one up in my 468....

 

[Hoss7979]

Ran some quick #'s to get ya in the ballpark of your engine build....454, oval port heads, 9.5:1, dual plane intake, 750 carb, large tube headers w/ mufflers.....

11-235-3 cam....
With 2.06/1.72 valves
---371HP @ 4500
---507TQ @ 2500
With 2.19/1.88 valves
---398HP @ 4500
---510TQ @ 3K

11-239-3 cam....
With 2.06/1.72 valves
---387HP @ 4500
---493TQ @ 3K
With 2.19/1.88
---409HP @ 4500
---501TQ @ 3500

And of course if you do some pocket porting/gasket match your gonna game some there as well....

 

[bp71k5]

Pics of the intake runners?

 

[Greg72]

Brian,

If you're looking for a dual-plane aluminum intake, I can probably help you out.

I've got a brand, new Air-Gap (already powdercoated so it's easy to keep clean) that's coming off my 502 when I swap my heads over....

edit.
Nevermind: EDL-7562 Rectangular Port BBC


-G

 

[bp71k5]

2 bolt mains:

 

[skunked]

oops

 

[bigblock72]

2 bolt mains:

That motor looks like it's in good shape, good score on that one.

The heads are definitely peanut port, the gasket outline matches a regular oval port.

The biggest problem with a stock 454 is the terribly low 7.7:1 compression ratio. If you could round up a set of vortec heads that aren't completely worn out you could give yourself a full point of compression with the small 100cc chambers and also step up to some decent intake ports. I personally think aluminum heads are kind of a waste without changing the pistons to get your compression up in the 9:1 range. Big blocks are not very octane tolerant so don't go above 9.5:1 or you'll never get it to stop pinging.

Cam choices are pretty easy, stay around 215-220 degrees of intake duration, 220-230 exhaust duration, 110-112 lobe center with a matching set of valve springs and you'll make over 500 ft lbs right off of idle even with peanut port heads. Make sure to use a lot of break in additive and break the cam in properly if using a flat tappet.

If you can swing it an aftermarket TBI setup will be a lot easier to tune and will make a little more power than the stock stuff. If the budget can't support it all then spend the money on engine internals first then swap the injection later. The factory TBI will do it with some patience and a large 454 size throttle body, at least 28 psi of fuel pressure and a bunch of time.

 

[80' 427]

They are obviously peanut ports. Larger ovals are noticeably larger. Using a Innovate to fool the factory tbi into leaning out supposedly gains substantial mpg

 

[bp71k5]

That motor looks like it's in good shape, good score on that one.

The heads are definitely peanut port, the gasket outline matches a regular oval port.

The biggest problem with a stock 454 is the terribly low 7.7:1 compression ratio. If you could round up a set of vortec heads that aren't completely worn out you could give yourself a full point of compression with the small 100cc chambers and also step up to some decent intake ports. I personally think aluminum heads are kind of a waste without changing the pistons to get your compression up in the 9:1 range. Big blocks are not very octane tolerant so don't go above 9.5:1 or you'll never get it to stop pinging.

Cam choices are pretty easy, stay around 215-220 degrees of intake duration, 220-230 exhaust duration, 110-112 lobe center with a matching set of valve springs and you'll make over 500 ft lbs right off of idle even with peanut port heads. Make sure to use a lot of break in additive and break the cam in properly if using a flat tappet.

If you can swing it an aftermarket TBI setup will be a lot easier to tune and will make a little more power than the stock stuff. If the budget can't support it all then spend the money on engine internals first then swap the injection later. The factory TBI will do it with some patience and a large 454 size throttle body, at least 28 psi of fuel pressure and a bunch of time.

Thanks that's helpful. Do you think an aftermarket roller cam retrofit would be worthwhile?

 

[Greg72]

Thanks that's helpful. Do you think an aftermarket roller cam retrofit would be worthwhile?

It's an expensive downward spiral Brian...... BTDT.

The engine in @NorCal69 's truck was my 454 that I couldn't stop saying "Might As Well" to.... I had Scott @4X4HIGH do the hydraulic cam retrofit on it, we found a spun main bearing which led to a complete new stroked rotating assembly..... larger valves...... it just kept snowballing.

I think the way you should play this game is get it put back together with the minimum cash outlay possible... maybe a new cam and some headers but that's where you should stop.


It's going to still take quite a bit of money and effort to get it installed and running... even dumb stuff like accessories and brackets end up costing a lot more than you realize.

Are you going to put EFI on this motor? That's a chunk also...


Even a "mild" BBC is going to be a real pleasure to drive with all that low-end TQ. A year from now, if you just can't stand having "only" 400HP/500TQ you could plan out a new BBC from scratch.

Just my $0.02 of course.


-G

 

[Hoss7979]

That motor looks like it's in good shape, good score on that one.

The heads are definitely peanut port, the gasket outline matches a regular oval port.

The biggest problem with a stock 454 is the terribly low 7.7:1 compression ratio. If you could round up a set of vortec heads that aren't completely worn out you could give yourself a full point of compression with the small 100cc chambers and also step up to some decent intake ports. I personally think aluminum heads are kind of a waste without changing the pistons to get your compression up in the 9:1 range. Big blocks are not very octane tolerant so don't go above 9.5:1 or you'll never get it to stop pinging.

Cam choices are pretty easy, stay around 215-220 degrees of intake duration, 220-230 exhaust duration, 110-112 lobe center with a matching set of valve springs and you'll make over 500 ft lbs right off of idle even with peanut port heads. Make sure to use a lot of break in additive and break the cam in properly if using a flat tappet.

If you can swing it an aftermarket TBI setup will be a lot easier to tune and will make a little more power than the stock stuff. If the budget can't support it all then spend the money on engine internals first then swap the injection later. The factory TBI will do it with some patience and a large 454 size throttle body, at least 28 psi of fuel pressure and a bunch of time.

Pass that good stuff out....lol Totally disagree w/ that!

It's an expensive downward spiral Brian...... BTDT.

The engine in @NorCal69 's truck was my 454 that I couldn't stop saying "Might As Well" to.... I had Scott @4X4HIGH do the hydraulic cam retrofit on it, we found a spun main bearing which led to a complete new stroked rotating assembly..... larger valves...... it just kept snowballing.

I think the way you should play this game is get it put back together with the minimum cash outlay possible... maybe a new cam and some headers but that's where you should stop.


It's going to still take quite a bit of money and effort to get it installed and running... even dumb stuff like accessories and brackets end up costing a lot more than you realize.

Are you going to put EFI on this motor? That's a chunk also...


Even a "mild" BBC is going to be a real pleasure to drive with all that low-end TQ. A year from now, if you just can't stand having "only" 400HP/500TQ you could plan out a new BBC from scratch.

Just my $0.02 of course.
-G

Like Greg said...sit down and really figure out what you want and then round up parts. Low compression is not ideal by any means, a good dual plane intake will wake it up along w/ carb or fuel injection. Also a good set of headers makes a world of diffence,,,,

Thanks that's helpful. Do you think an aftermarket roller cam retrofit would be worthwhile?

They help w/ friction but also cost a pretty penny more.....like the 11-235-3 compared to the 11-413-8 roller is $550....

 

[ashman]

Can't believe that Greg is in the "just get it running" camp, but I am too. It can turn into driveway art real fast if you start chasing.

 

[bigblock72]

Thanks that's helpful. Do you think an aftermarket roller cam retrofit would be worthwhile?

I'm with Greg on this one. It doesn't make sense to spend a grand (or more) on a roller cam setup on an otherwise low dollar build. In fact I would use one of the Summit cams like this one:
https://www.summitracing.com/parts/sum-k1301/overview/make/chevrolet
I have had good luck with this cam, just remember break-in is critical.

Keep the costs reasonable on this go around, if you want more later then build another motor later.

 

[bigblock72]

Pass that good stuff out....lol Totally disagree w/ that!

This debate should probably go in another thread. In truck type applications (cars don't load the motor near as much) when 91 octane is the best fuel available 9-9.2:1 is pretty much it, any more and the timing has to be retarded to the point power suffers.
My 72 has 9.7:1 and I can't even drive it a hot day even with 91 octane fuel and the timing cut back etc. it pings so bad going up grades or accelerating. The 8.1 in my suburban is the same way, it just retards the timing to the point where it can't get out of it's own way.
I've had several customers bring me motors with broken pistons that were at around 9.5 that pinged themselves to death. I ended up putting flattop pistons and a set of rod bearings in them and they are still running perfectly fine.

 

[82355]

You can make decent power with those peanut ports.

Martin

 

[Hoss7979]

If you were to go bigger valves this is a good kit to get...it gives you everything and the springs are good up to .560 lift. I've used on a set of 215 heads on a different engine....
http://www.competitionproducts.com/...ve-Hyd_Mech-FT/productinfo/8514/#.WRyhE00ksdU

 

[80' 427]

With a proper timing curve you can band aid low compression. Mine typically involves 26+ degrees of initial with a limited centri advance

 

[mrk5]

I ended up way over budget on my 454 swap with the nickel & dime stuff once I was actually mounting the motor in the truck. I budgeted the motor overhaul well enough but the other little things added up.

 

[bp71k5]

Only thing that made me consider the roller cam is the break-in process. I keep reading about all these guys wiping out cam lobes cause that made some unknown mistake. I hadn't checked on cost, but $500+ for the cam alone is money better spent elsewhere in my case. Really appreciate all he advice. I'll plan out the break-in process extra carefully.