404cid with ETP heads
404cid with ETP heads I am putting together a 6.0L block stroker which will come out to be a 404cid engine. It is a 4.000 inch stroke and a 4.010 inch bore (block did not need an excessive overbore) which will have an SCR of about 11.2:1. It is going in a back-halved 68 Camaro and will have a race weight of around 3000 pounds. The trans is a th400 with a 4000 stall converter. It will be carbureted and the cam is a hydraulic roller 239/243 @ .050 custom grind. I will adjust the rear end gear ratio accordingly but I am starting with 4.11s and a 28 inch tire. The car will see plenty of street time.
Question is:
Last week I ordered a set of ETP 225cc heads which are their 11 degree casting and I am wondering if I should not have optioned for the 240cc head. I have not done any LSx style engine in the past but at this point I am only thinking they cannot be too much different then anything else. Last year I built a pump gas 18 degree 421cid SBC which peaked at 6700rpm with a 248cc runner head. The SCR was about 11.3:1. It was 4.155 bore x 3.875 stroke and cam was a solid roller 256/265 @ .050. To me a 6700rpm peak is absolutely a street engine and that is about what I am shooting for in the 404cid LSx engine. I believe the intake runners on LSx heads are longer than an 18 degree SBC head so I am thinking the cross section of the 248cc heads was definitely larger. I know different style engines will have different behavior because of the many little differences but just in quick calculations of head volume to engine volume 248cc/421cid= 58.9% and 240cc/404cid= 59.4%. Does anyone have any thoughts here or experience with ETP heads? Thanks in advance.
Question is:
Last week I ordered a set of ETP 225cc heads which are their 11 degree casting and I am wondering if I should not have optioned for the 240cc head. I have not done any LSx style engine in the past but at this point I am only thinking they cannot be too much different then anything else. Last year I built a pump gas 18 degree 421cid SBC which peaked at 6700rpm with a 248cc runner head. The SCR was about 11.3:1. It was 4.155 bore x 3.875 stroke and cam was a solid roller 256/265 @ .050. To me a 6700rpm peak is absolutely a street engine and that is about what I am shooting for in the 404cid LSx engine. I believe the intake runners on LSx heads are longer than an 18 degree SBC head so I am thinking the cross section of the 248cc heads was definitely larger. I know different style engines will have different behavior because of the many little differences but just in quick calculations of head volume to engine volume 248cc/421cid= 58.9% and 240cc/404cid= 59.4%. Does anyone have any thoughts here or experience with ETP heads? Thanks in advance.
Last edited by melsie68; Dec 31, 2007 at 10:07 AM.
The 225s are the hot ticket in this particular setup I think! Being i'm not sure how the lsk cam lobes would fair in over 6800rpm situations with ls7 lifters and normal spring pressure and the heavier et valves i'd think the 225 head would make more average power then the 240 head so I'd say go this route. Can't wait to see it up and running!!!
no replies except from the guy down the hall from me? you guys might want to read this...
http://speedtalk.com/forum/viewtopic.php?t=8832
http://speedtalk.com/forum/viewtopic.php?t=8832
11 Second Club
Joined: Oct 2005
Posts: 1,847
Likes: 1
From: Sandwich, IL
You should talk to Cary @ ETP. I spent a half hour on the phone with him discussing the different head options for a 408 ci shortblock. He came straight up and said the ETP LS7 heads with an LS7 intake would be the best performer. 402,408,416,427 or 454 didn't matter he said. They all would benifit the most from LS7 style heads.
Now they are expensive. I think I paid $3400 for mine. But when you factor in how much money you save on the LS7 intake vs the fast 90 it helps offset some of that cost. Give him a call at 248-668-9390 or email him at cary@etheads.com.
Good luck.
Now they are expensive. I think I paid $3400 for mine. But when you factor in how much money you save on the LS7 intake vs the fast 90 it helps offset some of that cost. Give him a call at 248-668-9390 or email him at cary@etheads.com.
Good luck.
Thanks Darren for your reply. I am going carbureted on this engine and I already have the newer Super Victor intake for this build which uses a cathedral port design. So, I guess LS7 heads are out for me. I just want the engine to be a solid performer but not die off hard in the upper rpm because the heads are small. I have had engines which do that and I don't like it.
