MG Sports Cars

engine swaps and other performance upgrades, plus "factory" and Costello V8s

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windsurfhypo
Robert shoulder

(3 posts)

Registered:
07/27/2024 12:16PM

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MGB V8 Conversions HP
Posted by: windsurfhypo
Date: July 27, 2024 12:25PM

Any ideas I am rebuilding a MGB conversion with a 3500s 10.5.1 engine P6 and eldenbrook 4 barrel. Any idea of HP . This engine I think has more hp than other 3.5 rover engines so is it a good choice or should I look for another 3.5


Moderator
Curtis Jacobson
Portland Oregon
(4598 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: MGB V8 Conversions HP
Posted by: Moderator
Date: July 27, 2024 09:42PM

Welcome to BritishV8, Robert!

Rest assured that the Rover P6 variant is just fine, and no stock BOPR 3.5 has a significant performance advantage over it. 10.5:1 is a nice static compression number, if that's what you really have after rebuilding. Just make sure you're starting with undamaged parts, and then go with it. Focus your attention on doing a good job. When you outsource work be carefull to choose good shops.

But polling strangers and asking them to guess horsepower numbers is a waste of time, for countless reasons.

It sounds like you may still have many decisions to make concerning how to build-up your engine. Which camshaft to use? Or which pistons for that matter? Etc. That stuff can have a big effect on horsepower, torque, and "the area under the curve". All the little parts are important too, but for reliability. You'll find all sorts of good advice about that stuff here.

It's been over 30 years since I built my Buick 215. I've driven it in 46 of the United States so far. I've driven it in countless autocrosses and on track days. I've let a whole bunch of idiots borrow and thrash it. Everything from the camshaft downward is unchanged, whilst I've upgraded everything above the cam. No problems (aside from period-correct oil seal leakage;) because these are great engines. Driveability and reliability depend on quality work, so that should be your main focus. That, and enjoying the whole process. Have fun!


almimono
Almi Frank

(2 posts)

Registered:
06/29/2023 08:00AM

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Re: MGB V8 Conversions HP
Posted by: almimono
Date: November 06, 2024 07:04PM

Can you be kind enough to share pics once you're done building


Spitfire 350
Phil McConnell
Perrysburg, OH (Toledo area)
(258 posts)

Registered:
01/11/2010 09:19PM

Main British Car:
74 Spitfire 350Chevy

authors avatar
Re: MGB V8 Conversions HP
Posted by: Spitfire 350
Date: November 13, 2024 04:35PM

You are encouraged to share pics as you're building.


Greesent
Sam Miller

(5 posts)

Registered:
12/26/2024 09:19AM

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Re: MGB V8 Conversions HP
Posted by: Greesent
Date: January 04, 2025 08:34AM

A 3500S with an Edelbrock 4-barrel should be a pretty decent setup for an MGB. Hard to say exact HP without dyno numbers, but you're probably looking at somewhere in the 180-220 range, maybe more depending on the rest of the setup (exhaust, etc.). It's definitely a step up from a stock 3.5, so if you've already got it, I'd say go for it.


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