Engine and Transmission Tech

tips, technology, tools and techniques related to vehicle driveline components

Go to Thread: Previous•Next
Go to: Forum List•Message List•New Topic•Log In


tdecell
Trey Decell
MS
(31 posts)

Registered:
04/10/2010 12:13AM

Main British Car:
1974.5 MGB GT 3.9L Rover

authors avatar
3.9 Rover / 4.0 heads, any negatives regarding stock EFI?
Posted by: tdecell
Date: May 09, 2013 12:42AM

I've got a 1989 Rover 3.9 to go in my BGT, it's a 8.3:1 CR engine. I've read that 4.0 heads will increase compression ratio just a bit. I don't want to go too high,(don't really want to have to use premium fuel if I don't have to). I'm planning on using the factory 14cux EFI. Would raising the CR have any negative effects on the way the EFI operates? I was going to stay with a stock engine, but have come across a set of 4.0 heads for about $100 and am thinking about picking them up this weekend. Thoughts??


Moderator
Curtis Jacobson
Portland Oregon
(4577 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: 3.9 Rover / 4.0 heads, any negatives regarding stock EFI?
Posted by: Moderator
Date: May 09, 2013 03:28AM

You have to keep in mind that 8.3:1 is a very, very low starting point.


tdecell
Trey Decell
MS
(31 posts)

Registered:
04/10/2010 12:13AM

Main British Car:
1974.5 MGB GT 3.9L Rover

authors avatar
Re: 3.9 Rover / 4.0 heads, any negatives regarding stock EFI?
Posted by: tdecell
Date: May 09, 2013 08:17AM

That's why I wanted to go to the 4.0 heads... Get that pushed up a little bit Curtis.
Get Your BritishV8 T-shirt by clicking here


Go to: Forum List•Message List•New User Registration•Log In
Sorry, only registered users may post in this forum.