Too stroke or not to stroke!?
The machining is pretty standard stuff, but either you or your machinist will need to chamfer the bottom of the cylinders after they’re honed. The piston skirts will protrude below the bottom of the cylinders at BDC, which is not a problem unless the cylinders have a sharp edge at the bottom. The sharp edge will shave material off the skirts when the piston heads back towards TDC, so it needs to be chamfered or rounded off.
So I’m seeing two options for LS7 lifters, GM and the Delphi “LS7 style” lifters that are a bit less than the GM version. Should I go with the more expensive option, is there a difference in material or quality since Delphi is a gm parts manufacturer?
Yes Delphi Is a supplier for GM, but in the case of lifters for these engines, these are not original equipment. They are a re-boxed Item which is why they are listed as "LS7 Style".
If you dig deeper you will see some have had issues with the Delphi units.
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Joined: Jul 2013
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From: Portland, Oregon
Why even bother with OEM-style lifters? I wouldn't put LS7 lifters in a budget freshen up, much less a stroker build. Throw some nice link-bar low travel lifters in there. The valvetrain is not the place to start saving pennies. It should be a higher priority than adding stroke/displacement/boost.
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Why even bother with OEM-style lifters? I wouldn't put LS7 lifters in a budget freshen up, much less a stroker build. Throw some nice link-bar low travel lifters in there. The valvetrain is not the place to start saving pennies. It should be a higher priority than adding stroke/displacement/boost.
Why even bother with OEM-style lifters? I wouldn't put LS7 lifters in a budget freshen up, much less a stroker build. Throw some nice link-bar low travel lifters in there. The valvetrain is not the place to start saving pennies. It should be a higher priority than adding stroke/displacement/boost.
So the short block is back from the machine shop and found a place that had Johnson 2116 short throw link bar lifters, I ordered them. The shop that put the short block together is gonna measure for the pushrods when I get to that point. Is there anything else in the valve train I should consider replacing, I feel that my heads are pretty tight, they were put together with BTR Dual springs, I kept the stock rockers but did the trunion upgrade. Only about 10k miles on the entire setup.
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So the short block is back from the machine shop and found a place that had Johnson 2116 short throw link bar lifters, I ordered them. The shop that put the short block together is gonna measure for the pushrods when I get to that point. Is there anything else in the valve train I should consider replacing, I feel that my heads are pretty tight, they were put together with BTR Dual springs, I kept the stock rockers but did the trunion upgrade. Only about 10k miles on the entire setup.
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I just completed a 408. Those lifters are a good choice. Pushrod length is critical! Extra critical with not much room for error. Check with a comp tool multiple times, write it down and then call manton. Order their pushrods, they know how much to add or take away depending on how you measure. Run a quality dual spring and tool steel retainers. I can redline mine to 7500 no float. Shift at 7100. Hollow stem 2.08 valves. Tick stroker stage 1 cathedral cam.
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Joined: Jan 2017
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I run an MSD atomic ls1/2/6 intake that is ported
So I’m seriously rethinking using my current cam and heads for my new 408 build. I purchased a FAST 102 from a friend, and I’m thinking about doing a bigger cam and LS3 heads. Advanced Induction seems to be swamped with work and I can’t reach Phil and ask him about my ported 243’s and a bigger cam with the 408. Geoff at EPS advised that I’d need to change my 98 computer if I went the LS3 route. I like the cathedral ports for the torque that’s going to be made, but I’d also like to unlock more of the potential power a 408 can make with a bigger flowing head. Is there anyway I can get a little of both? I’d like ALOT of torque, good street manners, and be able to bust *** when needed.
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Joined: Aug 2009
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From: Coast of San Mateo County Between Pacifica & HMB
MMS 235s,AFR 230s,TFS 235s,PRCs with a
SCHMEDIUM ~ 239*/245* would be pretty killer with your Trans/Converter/Diff combo.
Should add 100 RWHP/80 LB' at peak and FATTER curve everywhere.
Great street manners and wicked throttle response.
My .02
SCHMEDIUM ~ 239*/245* would be pretty killer with your Trans/Converter/Diff combo.
Should add 100 RWHP/80 LB' at peak and FATTER curve everywhere.
Great street manners and wicked throttle response.
My .02
I couldn't get a response from AI either and I used alternate emails thinking maybe it was blocking my Main ISP to try and reach them. I ultimately had to go elsewhere.
I wouldnt Hesitate to go with a larger Aftermarket Cathedral head on the 408. They really need to breath on the top end and that is were most guys fall short.
I would definitely look in to Tony Mammo and his offerings for your application. He never fails to disappoint and may also enlighten you on things you hadn't considered for your build.
I wouldnt Hesitate to go with a larger Aftermarket Cathedral head on the 408. They really need to breath on the top end and that is were most guys fall short.
I would definitely look in to Tony Mammo and his offerings for your application. He never fails to disappoint and may also enlighten you on things you hadn't considered for your build.
On The Tree
Joined: May 2013
Posts: 189
Likes: 12
From: Newman Lake, WA
A bone stock 821 or 823 rec port head (LS3) will flow as much as even the very best ported 243 head on the intake side. It's on the exhaust side that the rec ports could use some help, but you can help them a bunch with camshaft design and save yourself some dough by not having them ported. If you have the cash, and want to have them ported, I'd highly recommend Total Engine Airflow's CNC programs. I use them exclusively for CNC porting.
If you do run the rec port heads stock (unported), increase the split between intake and exhaust duration. You've got plenty of converter, so I'd suggest something like a 236/248 or 238/250, on a 112, run it 4 degrees advanced, and about .360-.365 lobe lift if you're running stock rockers. Spring it accordingly. I'd recommend duals. Between the better heads, adding 60 cubic inches, and some more camshaft to feed it, you'll have a pretty sweet runner.
Your ECM won't know (or care) what heads you're running. As long as you have a 24x crank and 1x camshaft, you'll be good.
If you do run the rec port heads stock (unported), increase the split between intake and exhaust duration. You've got plenty of converter, so I'd suggest something like a 236/248 or 238/250, on a 112, run it 4 degrees advanced, and about .360-.365 lobe lift if you're running stock rockers. Spring it accordingly. I'd recommend duals. Between the better heads, adding 60 cubic inches, and some more camshaft to feed it, you'll have a pretty sweet runner.
Your ECM won't know (or care) what heads you're running. As long as you have a 24x crank and 1x camshaft, you'll be good.
A bone stock 821 or 823 rec port head (LS3) will flow as much as even the very best ported 243 head on the intake side. It's on the exhaust side that the rec ports could use some help, but you can help them a bunch with camshaft design and save yourself some dough by not having them ported. If you have the cash, and want to have them ported, I'd highly recommend Total Engine Airflow's CNC programs. I use them exclusively for CNC porting.
If you do run the rec port heads stock (unported), increase the split between intake and exhaust duration. You've got plenty of converter, so I'd suggest something like a 236/248 or 238/250, on a 112, run it 4 degrees advanced, and about .360-.365 lobe lift if you're running stock rockers. Spring it accordingly. I'd recommend duals. Between the better heads, adding 60 cubic inches, and some more camshaft to feed it, you'll have a pretty sweet runner.
Your ECM won't know (or care) what heads you're running. As long as you have a 24x crank and 1x camshaft, you'll be good.
If you do run the rec port heads stock (unported), increase the split between intake and exhaust duration. You've got plenty of converter, so I'd suggest something like a 236/248 or 238/250, on a 112, run it 4 degrees advanced, and about .360-.365 lobe lift if you're running stock rockers. Spring it accordingly. I'd recommend duals. Between the better heads, adding 60 cubic inches, and some more camshaft to feed it, you'll have a pretty sweet runner.
Your ECM won't know (or care) what heads you're running. As long as you have a 24x crank and 1x camshaft, you'll be good.
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Joined: Jul 2013
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From: Portland, Oregon
I would have used the AI 243's, cam, and Fast 90/90 on the 408, personally. Try a single plane intake and custom cam later.
But if you insist on the LS3 top end... here is something straight out of Tusky's cookbook:
416ci, LS3 heads untouched, LS3 intake untouched, 3450 lbs, 239/254 624/595 114+3 cam
10.49 @ 131.45 mph e.t
But if you insist on the LS3 top end... here is something straight out of Tusky's cookbook:
416ci, LS3 heads untouched, LS3 intake untouched, 3450 lbs, 239/254 624/595 114+3 cam
10.49 @ 131.45 mph e.t
On The Tree
Joined: May 2013
Posts: 189
Likes: 12
From: Newman Lake, WA
Thanks for that info! I think ima go ahead and get them ported. I messaged TEA through their site last week so hopefully I get a response soon. There’s a local guy who CNC ported my brothers 243’s and I’m really wanting to use him bc of what I’ve seen and the conversations we’ve had about his porting.
Updates……So, it’s been a while, I halted the build bc I ended up purchasing and mildly restoring a 66 mustang for my dad and surprised him on fathers day 2021. I wish I woulda ran across a running 67-69 Camaro for the same price and I woulda got him that instead. But he is a ford guy(hey you can’t choose your father!)…nah pops is TBE! ALSO….during the time of the mustang affair I found out I was going to be a dad for the first time, my big girl is almost 9 months old now. But daddy still needs his toys too so until I purchase a 2010+ CTS-V or 2010+ C6 I’m tryna build this ole 408.
I ran across this old thread it’s 65 pages I read the entire thread and this guy built this amazing 403 set up with ported L92 heads and cam specd by WCCCH. The car made 522/488 that got 21 mpg, was quiet and drove like a stock vehicle before he later converted to a 427.
https://ls1tech.com/forums/generatio...b-c-d-e-f.html
His build sounds like what I’ve always wanted especially now bc I wanna have my daughter with me and not have her exposed to all the noise and smelling of fuel like daddy. Guess I’ll have to look into a set of HF cats. Basically if anyone can chime back in and give me more input I’ll be greatly appreciative. AI is still not responding to email, I have two different top end engine setups to choose from and it’s like killing me be bc everyone’s advice here have been really good.
I ran across this old thread it’s 65 pages I read the entire thread and this guy built this amazing 403 set up with ported L92 heads and cam specd by WCCCH. The car made 522/488 that got 21 mpg, was quiet and drove like a stock vehicle before he later converted to a 427.
https://ls1tech.com/forums/generatio...b-c-d-e-f.html
His build sounds like what I’ve always wanted especially now bc I wanna have my daughter with me and not have her exposed to all the noise and smelling of fuel like daddy. Guess I’ll have to look into a set of HF cats. Basically if anyone can chime back in and give me more input I’ll be greatly appreciative. AI is still not responding to email, I have two different top end engine setups to choose from and it’s like killing me be bc everyone’s advice here have been really good.
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Your average 403 will make 470-480 in an auto and 500-530 in a stick car. I've heard great things from wcch. If you want a nice driving car that still moves out I would look into a set of ported ls6 heads from wcch or frankenstein, cam motions stealthy stroker cam or similar. You could run magnaflow high flow cats but they tend to burn up when you run them in big cam cars. From my experience, the fuel smell was replaced with a sulfur smell, so I took them off.
if you want something real quiet, see about incorporating a dynomax super turbo muffler into the build.
if you want something real quiet, see about incorporating a dynomax super turbo muffler into the build.
