roller block with gt40 heads.. valvetrain/airflow questions.
07-10-2013, 02:02 AM
#1
Thread Starter
Join Date: Jul 2013
Location: New Mexico
Posts: 6
roller block with gt40 heads.. valvetrain/airflow questions.
I don't know much about these engines. I'm going to run a carb setup, but that doesn't matter so much right here. I'm only asking a few questions about the cam/lifter/pushrod/rocker setup(s) that I can use. My block, cam, lifters, and pushrods are all from a town car hydraulic roller 5.0, rockers came on the gt40 heads. I traded a set of wheels for this motor, which a friend put together but has not started since changing the heads.
1. Will this work as it is?
2. If I were to change the cam to a cheap performance flat tappet setup, would I need both pushrods and lifters, or just lifters for compatability? Does anyone know where I can get a better roller cam for cheap instead for this setup?
3. exactly how much air can the gt40 heads flow? I wanna buy the right parts for my carb setup. I don't care what everyones favorite brand is, I wanna know about the relationship between airflow ratings of carb, intake manifold, heads, headers, and cam lift/duration.
I understand how all the parts work and what's going on, I just wanna know how close I should keep the ratings on all my parts and what I can reasonably expect to get through the gt40s without machine work.
Links are helpful, as are answers or explanations. I want numbers and facts, stories are okay too. Will disregard opinions. Sorry for asking so many questions on one thread, please answer question(s) 1, 2, or 3.
1. Will this work as it is?
2. If I were to change the cam to a cheap performance flat tappet setup, would I need both pushrods and lifters, or just lifters for compatability? Does anyone know where I can get a better roller cam for cheap instead for this setup?
3. exactly how much air can the gt40 heads flow? I wanna buy the right parts for my carb setup. I don't care what everyones favorite brand is, I wanna know about the relationship between airflow ratings of carb, intake manifold, heads, headers, and cam lift/duration.
I understand how all the parts work and what's going on, I just wanna know how close I should keep the ratings on all my parts and what I can reasonably expect to get through the gt40s without machine work.
Links are helpful, as are answers or explanations. I want numbers and facts, stories are okay too. Will disregard opinions. Sorry for asking so many questions on one thread, please answer question(s) 1, 2, or 3.
07-10-2013, 07:01 AM
#2
D.R. THE PATHETIC DORK
Join Date: Jun 2007
Location: West Virginia
Posts: 30,863
1.yes
2. no don't try a flat tappet in a roller block, you'd have to change all valvetrain parts = not worth it for a roll back in performance. A "b" cam is what you need and cam change = spring change
3. your stuck on price = cheap so matching all the right stuff will cost, just throw the almighty b cam in , a rpm air gap intake and 600-650 carb and swap springs on heads for cam choice and be done with it. = easiest solution for you and your budget
2. no don't try a flat tappet in a roller block, you'd have to change all valvetrain parts = not worth it for a roll back in performance. A "b" cam is what you need and cam change = spring change
3. your stuck on price = cheap so matching all the right stuff will cost, just throw the almighty b cam in , a rpm air gap intake and 600-650 carb and swap springs on heads for cam choice and be done with it. = easiest solution for you and your budget
07-10-2013, 07:48 AM
#3
5th Gear Member
Join Date: Jul 2012
Location: ohio
Posts: 3,628
I don't think Ive ever even heard of any one wanting to down grade to a flat tappet on a roller block . The cost of a B cam will be cheaper in the long run.
By the way , you will get a lot of opinions . Don't disregard all of them. As most opinions here are formed from facts.
By the way , you will get a lot of opinions . Don't disregard all of them. As most opinions here are formed from facts.
07-10-2013, 01:45 PM
#4
4th Gear Member
Join Date: Jun 2011
Location: Indy
Posts: 1,353
Listen to Mjr, he's definitely steering you in the right direction. As for question #3, read read read, then read some more. These engines are one of the easiest to work on, you just need a little know-how. Google is your friend here, and a lot of us learned by trial & error, you'll learn pretty quick which opinions to rule out. Is this going in that RX-7?
07-10-2013, 03:40 PM
#5
Thread Starter
Join Date: Jul 2013
Location: New Mexico
Posts: 6
1.yes
2. no don't try a flat tappet in a roller block, you'd have to change all valvetrain parts = not worth it for a roll back in performance. A "b" cam is what you need and cam change = spring change
3. your stuck on price = cheap so matching all the right stuff will cost, just throw the almighty b cam in , a rpm air gap intake and 600-650 carb and swap springs on heads for cam choice and be done with it. = easiest solution for you and your budget
2. no don't try a flat tappet in a roller block, you'd have to change all valvetrain parts = not worth it for a roll back in performance. A "b" cam is what you need and cam change = spring change
3. your stuck on price = cheap so matching all the right stuff will cost, just throw the almighty b cam in , a rpm air gap intake and 600-650 carb and swap springs on heads for cam choice and be done with it. = easiest solution for you and your budget
What is the rpm range of the b cam with some good springs and possibly roller rockers on a gt40 head?
07-10-2013, 03:44 PM
#6
Thread Starter
Join Date: Jul 2013
Location: New Mexico
Posts: 6
Listen to Mjr, he's definitely steering you in the right direction. As for question #3, read read read, then read some more. These engines are one of the easiest to work on, you just need a little know-how. Google is your friend here, and a lot of us learned by trial & error, you'll learn pretty quick which opinions to rule out. Is this going in that RX-7?
07-10-2013, 03:58 PM
#7
5th Gear Member
Join Date: Jul 2012
Location: ohio
Posts: 3,628
Ive seen what stock 5.0 can do in a rx7 , I almost bought one a couple years ago, but the guy wanted to much for it. Was a really quick car. And don't worry about having to rev high with the 4.10 gearing youll be red lining almost as fast as you can blink an eye in first with the t5. A 650 or 750 carb will make all the power the thing can take , in fact your probly gonna go through some tires till you get the suspension dial in.
07-10-2013, 04:34 PM
#8
Thread Starter
Join Date: Jul 2013
Location: New Mexico
Posts: 6
Ive seen what stock 5.0 can do in a rx7 , I almost bought one a couple years ago, but the guy wanted to much for it. Was a really quick car. And don't worry about having to rev high with the 4.10 gearing youll be red lining almost as fast as you can blink an eye in first with the t5. A 650 or 750 carb will make all the power the thing can take , in fact your probly gonna go through some tires till you get the suspension dial in.
07-10-2013, 06:36 PM
#9
D.R. THE PATHETIC DORK
Join Date: Jun 2007
Location: West Virginia
Posts: 30,863
07-10-2013, 06:40 PM
#10
D.R. THE PATHETIC DORK
Join Date: Jun 2007
Location: West Virginia
Posts: 30,863