My 241s on a 408...
Thread Starter
Joined: Nov 2004
Posts: 309
Likes: 0
From: Metro Detroit
My 241s on a 408... Looking at a 408 iron block now... Just wondering what needs to be done to my ported 241s to make them work well on a larger bore set up. What size valves can I upgrade to? Looks like a little more material could be taken out around the valves but im no head porter... How much would I have to mill to get them around 11 ish to 1 CR?
maybe he doesn't have $2500 to spend on the heads alone
call up one of the vendors who do porting, and talk with them. i'm sure they can steer you in the right direction.
241s won't be ideal on a 408, but if its what you have...its what you have.
nice thing is that if they are hogged out and the runners are big...they will actually fit the 408 better than they would a 346.
some ported 241s can easily end up having a 225-230cc intake runner....which would kill low end on a 346, but they will fit the needs of the stroker much better.
call up one of the vendors who do porting, and talk with them. i'm sure they can steer you in the right direction.
241s won't be ideal on a 408, but if its what you have...its what you have.
nice thing is that if they are hogged out and the runners are big...they will actually fit the 408 better than they would a 346.
some ported 241s can easily end up having a 225-230cc intake runner....which would kill low end on a 346, but they will fit the needs of the stroker much better.
my buddy made 450/435 untuned stuck in open loop on STOCK 241 heads and a patrick g cam.HE ran an 11.6 at 120. they will do pretty good with a tune and porting around the bowl area and on the ehxaust side. id guess 475whp-480
Trending Topics
We did some 853 heads on a 408 bottom end for a good friend of mine. They were unmilled with stock valves, I just cleaned up the ports a little myself (and I don't claim to know anything about porting heads). We slapped a used cam I picked up that was a 252/256 dur. @ .050" with something like .640 lift on a 113 LSA.
The end result was 470 rwhp and the torque was in the 470's, just not sure of the exact number.
This was using pacesetter 1 3/4" headers and an Ls6 intake.
Basically, he needed a bottom end because it threw a rod so we fixed it with a 408 as cheap as we possibly could.
The end result was 470 rwhp and the torque was in the 470's, just not sure of the exact number.
This was using pacesetter 1 3/4" headers and an Ls6 intake. Basically, he needed a bottom end because it threw a rod so we fixed it with a 408 as cheap as we possibly could.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
We did some 853 heads on a 408 bottom end for a good friend of mine. They were unmilled with stock valves, I just cleaned up the ports a little myself (and I don't claim to know anything about porting heads). We slapped a used cam I picked up that was a 252/256 dur. @ .050" with something like .640 lift on a 113 LSA.
The end result was 470 rwhp and the torque was in the 470's, just not sure of the exact number. This was using pacesetter 1 3/4" headers and an Ls6 intake.
Basically, he needed a bottom end because it threw a rod so we fixed it with a 408 as cheap as we possibly could.
The end result was 470 rwhp and the torque was in the 470's, just not sure of the exact number.
This was using pacesetter 1 3/4" headers and an Ls6 intake. Basically, he needed a bottom end because it threw a rod so we fixed it with a 408 as cheap as we possibly could.
Thread Starter
Joined: Nov 2004
Posts: 309
Likes: 0
From: Metro Detroit
maybe he doesn't have $2500 to spend on the heads alone
call up one of the vendors who do porting, and talk with them. i'm sure they can steer you in the right direction.
241s won't be ideal on a 408, but if its what you have...its what you have.
nice thing is that if they are hogged out and the runners are big...they will actually fit the 408 better than they would a 346.
some ported 241s can easily end up having a 225-230cc intake runner....which would kill low end on a 346, but they will fit the needs of the stroker much better.
call up one of the vendors who do porting, and talk with them. i'm sure they can steer you in the right direction.
241s won't be ideal on a 408, but if its what you have...its what you have.
nice thing is that if they are hogged out and the runners are big...they will actually fit the 408 better than they would a 346.
some ported 241s can easily end up having a 225-230cc intake runner....which would kill low end on a 346, but they will fit the needs of the stroker much better.
About the hogged out runners, If you look a my Tq numbers(368 peek) they do look a little low for a heads/cam car. Anyone think this could be because the runners are too large for a 346? I know it would be hard to tell but how do the pics look?
Thread Starter
Joined: Nov 2004
Posts: 309
Likes: 0
From: Metro Detroit
We did some 853 heads on a 408 bottom end for a good friend of mine. They were unmilled with stock valves, I just cleaned up the ports a little myself (and I don't claim to know anything about porting heads). We slapped a used cam I picked up that was a 252/256 dur. @ .050" with something like .640 lift on a 113 LSA.
The end result was 470 rwhp and the torque was in the 470's, just not sure of the exact number. This was using pacesetter 1 3/4" headers and an Ls6 intake.
Basically, he needed a bottom end because it threw a rod so we fixed it with a 408 as cheap as we possibly could.
The end result was 470 rwhp and the torque was in the 470's, just not sure of the exact number.
This was using pacesetter 1 3/4" headers and an Ls6 intake. Basically, he needed a bottom end because it threw a rod so we fixed it with a 408 as cheap as we possibly could.
I used my 241's on 382 with 2.05-1.570 valves that came with Stage 2 CNC from ETP. Check on a Stage 3 CNC port job. It will probably work very well. By the way, I'm at 486RWHP, 455RWT. You'll do better.
Looking at a 408 iron block now... Just wondering what needs to be done to my ported 241s to make them work well on a larger bore set up. What size valves can I upgrade to? Looks like a little more material could be taken out around the valves but im no head porter... How much would I have to mill to get them around 11 ish to 1 CR?
Thread Starter
Joined: Nov 2004
Posts: 309
Likes: 0
From: Metro Detroit
Is the exhaust port round and the size of a golfball now? Just wondering. Make the best of your heads if possible. An aftermarket head would be a better choice imo. Since your on a budget, get a set of good used patriots, pay a local head porter $400 bucks or so and have them tuned up and the chamber opened up to your bore size.
throw on your 241's and go enjoy your car!!! your obviously going to be making 460-470 hp at the rear wheels ON A BUDGET! and that aint bad... save up for a couple years for new heads you can and then pick up that extra horsepower if you want.
What size valves are in them right now? I would have a 2.04 intake with a 1.57 or 1.60 exhaust valve installed on the stock seats. Then, have a valvejob done with a radius throat cut and deshrouding cuts done to the chambers. With that work and blending the throat cut you should pick up a good amount of power.
The milling is completely dependent upon what size your valve reliefs in your pistons are, what head gaskets you run, and how much in or out of the hole the pistons are. Roughly milling .007 is equivalent to removing 1cc of material from the combustion chambers.
The milling is completely dependent upon what size your valve reliefs in your pistons are, what head gaskets you run, and how much in or out of the hole the pistons are. Roughly milling .007 is equivalent to removing 1cc of material from the combustion chambers.
"About the hogged out runners, If you look a my Tq numbers(368 peek) they do look a little low for a heads/cam car. Anyone think this could be because the runners are too large for a 346? I know it would be hard to tell but how do the pics look?"
that does seem low for that cam.
hell with a crappy tune my Torquer V1 made ~375ftlbs on STOCK heads
and actually i'll be getting new dyno numbers tomorrow....and then throwing a FAST on it and checking for gains.
i'll try to update.
but i think your torque is WAY low!!
that does seem low for that cam.
hell with a crappy tune my Torquer V1 made ~375ftlbs on STOCK heads
and actually i'll be getting new dyno numbers tomorrow....and then throwing a FAST on it and checking for gains.
i'll try to update.
but i think your torque is WAY low!!
