Another L48 upgrade topic...
Thread Starter
Melting Slicks
Joined: Jul 2002
Posts: 3,000
Likes: 22
From: Boulder Creek California
Another L48 upgrade topic...
Hi. I'll soon be selling my old trombone for about $1500, and would like to put it towards a big performance boost. I had not been planning on having such a large sum of cash, so I haven't quite thought this through yet! Less cost is naturally better, more for the rest of the car!
I am looking to build a new topend on my '77 L48. I've heard good things about Vortec and Dart Iron Eagle heads. I'd prefer the Vortec for cost reasons but the greater options allowed by other heads are attractive. I also plan to replace the intake manifold and cam.
Things I'd like to keep:
2" true dual exhaust with stock exhaust manifolds
Just rebuilt original carb (if possible)
Otherwise stock engine
I'd like to make over 300 horses and equally respectable torque. 1/4 mile times would be nice, but a fast daily driver is what I'm looking for. I hear I will get better mileage with modern heads but as long as I don't get less than the 10-12ish I get now, I'll be happy. The engine was rebuilt less than 3000 miles ago, 2 miles previous to my buying it (and 15 years ago!)
Well...let me know if there are other relevant details I've forgotten! Thanks in advance!
I am looking to build a new topend on my '77 L48. I've heard good things about Vortec and Dart Iron Eagle heads. I'd prefer the Vortec for cost reasons but the greater options allowed by other heads are attractive. I also plan to replace the intake manifold and cam.
Things I'd like to keep:
2" true dual exhaust with stock exhaust manifolds
Just rebuilt original carb (if possible)
Otherwise stock engine
I'd like to make over 300 horses and equally respectable torque. 1/4 mile times would be nice, but a fast daily driver is what I'm looking for. I hear I will get better mileage with modern heads but as long as I don't get less than the 10-12ish I get now, I'll be happy. The engine was rebuilt less than 3000 miles ago, 2 miles previous to my buying it (and 15 years ago!)
Well...let me know if there are other relevant details I've forgotten! Thanks in advance!
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
Re: Another L48 upgrade topic... (RUXperienced)
XE256 cam if you really wanna keep the exhaust manifolds, but I'd recommend you step up to the XE262 and headers, it'll make the experience all the better.
Vortecs on the cheap, the Iron Eagles are much more serious heads, they'd go great with an XE268 and headers.
With Vortecs, XE262 and headers, expect ~320 hp.
Vortecs, XE256, and stock manifolds, ~260-270?
-Steve
Vortecs on the cheap, the Iron Eagles are much more serious heads, they'd go great with an XE268 and headers.
With Vortecs, XE262 and headers, expect ~320 hp.
Vortecs, XE256, and stock manifolds, ~260-270?
-Steve
Safety Car
Joined: Aug 2001
Posts: 3,685
Likes: 202
From: Waterford Mi
Re: Another L48 upgrade topic... (Pacin'California)
Crane Cam #272 and the Dart 64cc heads will get you close. To get the best performance you will need headers and a change in your rear gear. High flow heads and high lift cam won't do much good if the gear is less than 3.73.
Thread Starter
Melting Slicks
Joined: Jul 2002
Posts: 3,000
Likes: 22
From: Boulder Creek California
Re: Another L48 upgrade topic... (redwingvette)
Thanks guys. More suggestions? And what intake manifold would be well matched to the suggested heads? Will the old 4-jet be sufficient or will I have to budget for a new carb?
Team Owner
Joined: Jun 2001
Posts: 43,136
Likes: 155
From: Thomson Georgia
Re: Another L48 upgrade topic... (redwingvette)
Crane Cam #272 and the Dart 64cc heads will get you close. To get the best performance you will need headers and a change in your rear gear. High flow heads and high lift cam won't do much good if the gear is less than 3.73.
Drifting
Joined: Nov 2000
Posts: 1,361
Likes: 0
From: Honolulu Hawaii
Re: Another L48 upgrade topic... (RUXperienced)
If you are starting from a stock setup, doing the Vortec head & intake upgrade is a great bang for the buck. Stick with a mild cam with under .450" lift & you can use the springs that come with the assembled Vortec head. I believe Edelbrock makes a Vortec performer manifold that will accept the Q-jet. I don't think you'll need much more to hit your 300 hp goal. Good luck!
Thread Starter
Melting Slicks
Joined: Jul 2002
Posts: 3,000
Likes: 22
From: Boulder Creek California
Re: Another L48 upgrade topic... (nunus79)
Well that's exactly what I hoped (and wanted) to hear! :yesnod: I will listen to any more suggestions of course, but this is looking like a good route. Thanks alot guys!
-Chris
-Chris
