Engine and Transmission Tech
tips, technology, tools and techniques related to vehicle driveline components
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Re: 4.5/4.9 Cadillac V8
Perhaps this helps explain the "weird" center intake ports on each side ? Runner length vs velocity, with a single plane ? I want to install an Eaton M112. I suspect a modded single plane will work better, Jim ?
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mgb260 Jim Nichols Sequim,WA (2463 posts) Registered: 02/29/2008 08:29PM Main British Car: 1973 MGB roadster 260 Ford V8 |
Re: 4.5/4.9 Cadillac V8
This guy used a M90:
[www.fiero.nl] Another: [www.fiero.nl] Edited 1 time(s). Last edit at 10/21/2023 06:29PM by mgb260. |
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mgb260 Jim Nichols Sequim,WA (2463 posts) Registered: 02/29/2008 08:29PM Main British Car: 1973 MGB roadster 260 Ford V8 |
Re: 4.5/4.9 Cadillac V8
The single plane small throttle bores for the early 4.5 are a carryover from the 4.1. Probably same intake. Need to be bored bigger. The dual plane on later 4.5 and 4.9 are much larger.
Edited 1 time(s). Last edit at 10/22/2023 12:54PM by mgb260. |
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mgb260 Jim Nichols Sequim,WA (2463 posts) Registered: 02/29/2008 08:29PM Main British Car: 1973 MGB roadster 260 Ford V8 |
Re: 4.5/4.9 Cadillac V8
Art, The Allante lower intake would be best for a Supercharger. Will only work with 90 4.5 PFI or 4.9 heads.
Edited 1 time(s). Last edit at 10/22/2023 12:41PM by mgb260. |
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BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6470 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: 4.5/4.9 Cadillac V8
It would be pretty easy to make a blower intake for that.
When they redesigned the lifter mount did they run the individual lifter bolts into the head? Jim |
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mgb260 Jim Nichols Sequim,WA (2463 posts) Registered: 02/29/2008 08:29PM Main British Car: 1973 MGB roadster 260 Ford V8 |
Re: 4.5/4.9 Cadillac V8
Jim, They made a couple of dog legs in the valve cover sealing area due to injector locations. If a person wanted to go carb or TBI the injector holes would have to be plugged. 88-90 4.5 are TBI and 91-95 4.9 are PFI. 88-90 4.5 and 91-95 4.9 all use the ribbed reinforced block. The only carryover is the 4.5 used the old style oil pump that should be swapped to the 4.9 pump. The 4.5 has shorter stroke and longer rods than the 4.9. Everyone should avoid the 4.1 motor except a few parts like the oil pan or valve covers.
Edited 1 time(s). Last edit at 10/22/2023 10:51PM by mgb260. |
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mgb260 Jim Nichols Sequim,WA (2463 posts) Registered: 02/29/2008 08:29PM Main British Car: 1973 MGB roadster 260 Ford V8 |
Re: 4.5/4.9 Cadillac V8
Jim, that reminds me. The lifter angle of the older motors with flat tappets and removing Zinc from oil caused early wear to the cam lobes. The gasket materials and Dexcool anti-freeze were issues. Also the early blocks had porosity and cracking issues. The small 4. 1 was also stressed pushing the weight of a heavy car. As far as stock net HP rating the 4.9 with 200HP and 275TQ look pretty good compared to 302 Ford or 307 Chevy that were not over 180HP and 250TQ. The 4.5 Allante was rated 220HP due to the better intake manifold.
Edited 1 time(s). Last edit at 10/23/2023 10:27PM by mgb260. |
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Re: 4.5/4.9 Cadillac V8, big mains, small rods
I see their logic. Big mains give more rigidity and crank pin overlap.Small rods reduces I loads and makes a smaller rod ark. Plus it has hyd. rolled fillets on RJ's
Onward, Art. |
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mgb260 Jim Nichols Sequim,WA (2463 posts) Registered: 02/29/2008 08:29PM Main British Car: 1973 MGB roadster 260 Ford V8 |
Re: 4.5/4.9 Cadillac V8
Carl, I meant after 72 when they went to "Net" HP. The Caddy if around pre-smog would still be higher than the Ford or Chevy!
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BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6470 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: 4.5/4.9 Cadillac V8
He was wrong about one thing, the fan drag he showed was probably pretty close. At room temperature it would be fully engaged and only disengages as the temp of the air from the radiator goes up.
Running the fan inside a shroud and with resistance to airflow from the radiator might increase the load some, I don't know how much. But to me the takeaway from this was that between the fan, headers, and intake system that we run on the MGB we probably don't have that much difference between the gross and net HP since we are basically just dragging along the water pump and alternator. Jim |
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mgb260 Jim Nichols Sequim,WA (2463 posts) Registered: 02/29/2008 08:29PM Main British Car: 1973 MGB roadster 260 Ford V8 |
Re: 4.5/4.9 Cadillac V8
Power steering Hydraulic pump and AC compressor was also figured in the Net HP ratings. 74-84 had more smog control, ran hotter and leaner. Also had retarded timing, so were pretty gutless.
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MGBV8 Carl Floyd Kingsport, TN (4514 posts) Registered: 10/23/2007 11:32PM Main British Car: 1979 MGB Buick 215 |
Re: 4.5/4.9 Cadillac V8
My 215 is a 1963 JN block 11:1 comp. rated 200 HP that was rebuild back all standard. Rear wheel dyno'd at 162 HP. In this case, gross & net horsepower are very close to the same.
The '67-'69 Chevy 302 real world HP was considerably higher than the advertised gross HP. :) |
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mgb260 Jim Nichols Sequim,WA (2463 posts) Registered: 02/29/2008 08:29PM Main British Car: 1973 MGB roadster 260 Ford V8 |
Re: 4.5/4.9 Cadillac V8
88-89 4.5 has smaller Rover sized valves. 90-91 Allante 4.5 has the same larger valves as 91-95 4.9. The Allante 4.5 has longer connecting rods and the shorter 4.9 pistons. This may be helpful for those that mix and match parts.
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mgb260 Jim Nichols Sequim,WA (2463 posts) Registered: 02/29/2008 08:29PM Main British Car: 1973 MGB roadster 260 Ford V8 |
Re: 4.5/4.9 Cadillac V8
Hypothetical 4.9 build. Ported heads, cam specs similar to Ford 5.0 HO roller. 600cfm Holley carb, headers.
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mgb260 Jim Nichols Sequim,WA (2463 posts) Registered: 02/29/2008 08:29PM Main British Car: 1973 MGB roadster 260 Ford V8 |
Re: 4.5/4.9 Cadillac V8
Looks a little better spread out to show the nice torque curve.
Edited 1 time(s). Last edit at 02/24/2024 08:47PM by mgb260. |
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Re: 4.5/4.9 Cadillac V8
Is there a flow bench report for ported 4.9L.heads ? Using an M90 blower on a 4,9L. sounds out-matched. Any temp rise and boost data ?
Thanks, Art |
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