'96 252 454 Magnum performance benchmark

[Patriot 8713]

Sounds nice. I think we need to go to the north and give Bob a ride. Lol
He'll get that 430 yet.
Do you have a before idle vid? These things do idle low. Still supprised about that.
Is this close enough to that request patriot?
https://youtu.be/QGOH_7LhAxI

I didn't know you had the tune on yours. That sounds good, but akorcovelos sounds like it has a higher lift/duration cam in it now!

[Big Block Power]

Sounds nice. I think we need to go to the north and give Bob a ride. Lol
He'll get that 430 yet.
Do you have a before idle vid? These things do idle low. Still supprised about that.
Is this close enough to that request patriot?
https://youtu.be/QGOH_7LhAxI

I didn't know you had the tune on yours. That sounds good, but akorcovelos sounds like it has a higher lift/duration cam in it now!

Just did it this winter too. Captains call might help that some. Yes his sounds nice. It would be cool to see the the diff in what they all changed. I was going after very specific things in mine.
There is a very big diff in the gi and gxi idle and cam. I'm sure the same is true in the merc 496 mag and ho.

[Patriot 8713]

Sounds nice. I think we need to go to the north and give Bob a ride. Lol
He'll get that 430 yet.
Do you have a before idle vid? These things do idle low. Still supprised about that.
Is this close enough to that request patriot?
https://youtu.be/QGOH_7LhAxI

I didn't know you had the tune on yours. That sounds good, but akorcovelos sounds like it has a higher lift/duration cam in it now!

Just did it this winter too. Captains call might help that some. Yes his sounds nice. It would be cool to see the the diff in what they all changed. I was going after very specific things in mine.
There is a very big diff in the gi and gxi idle and cam. I'm sure the same is true in the merc 496 mag and ho.

They both sound great. It would be interesting to know the cam specs between Mercruiser and Volvo big blocks.

How much MPH did you gain on yours with the tune. Do you have a thread with all your tune info?

[cmattj]

They both sound great. It would be interesting to know the cam specs between Mercruiser and Volvo big blocks.

How much MPH did you gain on yours with the tune. Do you have a thread with all your tune info?

Please return to Chapter 1. We will be sending out quizzes tomorrow on the mph estimates .
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Here you go
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viewtopic.php?f=47&t=1933

[akorcovelos]

Sounds nice. I think we need to go to the north and give Bob a ride. Lol
He'll get that 430 yet.
Do you have a before idle vid? These things do idle low. Still supprised about that.
Is this close enough to that request patriot?
https://youtu.be/QGOH_7LhAxI

This was the stock tune:


Not sure on Volvo specs, but the Mag cam is as follows:

The 454/502 Magnum flat lifter camshaft has 224/224 duration .510/.510 lift 115.5 LSA.

[Big Block Power]

It sounds diff. This is the mer 496 specs. Couldn't find Volvos. It must be with they're torque specs.
But I think merc uses a flat cam. Volvo uses a roller. It was hard to tell. No good pictures from merc and it's getting late and running out of time to search more. The volvo cam I could cross ref to a gm number. Merc I couldn't.

[akorcovelos]

Yup, the Merc is a flat cam. Here is the full post with cam info I found on OSO:

Here is some info from Dennis Moore on this forum - can find the link again, but here is the info - hope it's not too late. Durations given at .050" lift, and lift at the valve of course. Seems like very wide lobe centers on those cams compared to aftermarket.

"The factory GM specs are;

The flat lifter 7.4/330 horsepower camshaft is an old design camshaft from the 60's with 213/217 duration .460/.480 lift 114 LSA.

The 454/502 Magnum flat lifter camshaft has 224/224 duration .510/.510 lift 115.5 LSA.

The roller lifter 7.4/Gen VI/Vortech L29 camshaft has 206/211 duration .480/.483 lift 115.5 LSA.

The roller lifter 454/502 Magnum camshaft has 224/224 duration .483/.483 lift 115.5 LSA

These camshafts were removed from marine engines by me and measured by Comp Cams for my book BIG BLOCK CHEVY MARINE PERFORMANCE. They each came back from Comp Cams with specs that showed one degree more duration on each lobe than the factory GM specs (above).

Although these camshafts may seem to have a large amount of duration at .050 check they are very mild because they have slow opening and closing flanks for durability reasons. The flat lifter 7.4 camshaft is extremly mild compared to a new aftermarket camshaft."

Alan

[cmattj]

Always good reads in cam profiles. I like that the the marine performance cams are on a 114/112 lobe center. Nasty low vacuum idle but still conservative for fear of water reversion . Imagine getting a 108 Lobe center to not drink water back in , and how much more power could be made at 4500-5500 rpm.
Is the 454 magnum a hydraulic roller like the 502 of that era?
I’m sure that’s in your future upgrade if not!

[Patriot 8713]

They both sound great. It would be interesting to know the cam specs between Mercruiser and Volvo big blocks.

How much MPH did you gain on yours with the tune. Do you have a thread with all your tune info?

Please return to Chapter 1. We will be sending out quizzes tomorrow on the mph estimates .
.
Here you go
.
viewtopic.php?f=47&t=1933

I was actually asking if BBP had a thread on his tune.

[akorcovelos]

Always good reads in cam profiles. I like that the the marine performance cams are on a 114/112 lobe center. Nasty low vacuum idle but still conservative for fear of water reversion . Imagine getting a 108 Lobe center to not drink water back in , and how much more power could be made at 4500-5500 rpm.
Is the 454 magnum a hydraulic roller like the 502 of that era?
I’m sure that’s in your future upgrade if not!

1996 was a transition year from solid to roller, I'll have to look up the block casting to see which it is, now I'm curious. The 454/502 are almost identical, even use the same cam & heads. Cam and headers are next on the list, so I'll nee to know this stuff anyway.

good info here: https://www.perfprotech.com/blog/articl ... eplacement

[cmattj]

I was actually asking if BBP had a thread on his tune.

Ok Patriot.. I gotta put down the lemonade and read more BBP will chime in soon as he is yet to test it.

Always good reads in cam profiles. I like that the the marine performance cams are on a 114/112 lobe center. Nasty low vacuum idle but still conservative for fear of water reversion . Imagine getting a 108 Lobe center to not drink water back in , and how much more power could be made at 4500-5500 rpm.
Is the 454 magnum a hydraulic roller like the 502 of that era?
I’m sure that’s in your future upgrade if not!

1996 was a transition year from solid to roller, I'll have to look up the block casting to see which it is, now I'm curious. The 454/502 are almost identical, even use the same cam & heads. Cam and headers are next on the list, so I'll nee to know this stuff anyway.

good info here: https://www.perfprotech.com/blog/articl ... eplacement

Nice. Either way you can upgrade it. I went with a Comp cams "extreme marine" version years ago when I did my 502 in my 22 Donzi. It was great from 3000 rpm to 5200 and idle was good. The thought was going with the higher EMI manifolds that water reversion fear would be less of an issue over the stock manifolds. Gotta love water in the exhaust system right? Since we are doing Idle clips.. here you go
.

[Patriot 8713]

I was actually asking if BBP had a thread on his tune.

Ok Patriot.. I gotta put down the lemonade and read more BBP will chime in soon as he is yet to test it

Always good reads in cam profiles. I like that the the marine performance cams are on a 114/112 lobe center. Nasty low vacuum idle but still conservative for fear of water reversion . Imagine getting a 108 Lobe center to not drink water back in , and how much more power could be made at 4500-5500 rpm.
Is the 454 magnum a hydraulic roller like the 502 of that era?
I’m sure that’s in your future upgrade if not!

1996 was a transition year from solid to roller, I'll have to look up the block casting to see which it is, now I'm curious. The 454/502 are almost identical, even use the same cam & heads. Cam and headers are next on the list, so I'll nee to know this stuff anyway.

good info here: https://www.perfprotech.com/blog/articl ... eplacement

Nice. Either way you can upgrade it. I went with a Comp cams "extreme marine" version years ago when I did my 502 in my 22 Donzi. It was great from 3000 rpm to 5200 and idle was good. The thought was going with the higher EMI manifolds that water reversion fear would be less of an issue over the stock manifolds. Gotta love water in the exhaust system right? Since we are doing Idle clips.. here you go
.

I wasn't very clear on who I was talking to...things get confusing when I hijack threads! lol

The Donzi sounds awesome!

[akorcovelos]

Awesome info! now I know what cam to get, lol, sounds great I bet it flew! That smile at the end tells it all, I make the same face every time I start mine up.

[akorcovelos]

I would love to hear a Whipple tuned 496HO!

Here you go: https://whipplesuperchargers.com/index. ... duct_id=52

STAGE 2
The Whipple stage 2 maximizes the power output of the stock engine by running 91 octane or better, increasing the maximum spark advance, increased ignition power from the individual coils, denser air charge from the low temp thermostat and maximized air-fuel ratio in each individual cylinder. Calibration increases torque levels throughout the entire rpm curve while making more peak hp for increased speeds. Customers report far cleaner transoms (less soot) while increased throttle response.
Key features:
• Hi-performance PCM calibration
• Low-temp thermostat
• 5450 RPM limit
• 5% - 8% power increase over stock
• Increased acceleration with increased torque output

[Patriot 8713]

I want mine to sound like this.



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