406 Questions
406 Questions Hey guys I've been into Ls1 for alittle too long and going to be putting my 66' Chevelle back together and have some questions.
I'm pulling my 355' out and i have a 406 i'm gathering parts for. I already have a forged crank, rods, no pistons yet? And Canfield 215 heads w/2.08 valves and solid roller springs and a Victor Jr. intake. What i do know is it will be on a direct port kit about a 250hit so i would like to know and hear some opinons on what pistons,compression and if i need to port these heads i know nothing about these heads and what cam these 406's and these heads like.
I'm shooting for a streetable low 10 second car hear. Can i get these heads to work and flow! I was thinking about 12.5 Compression and JE pistons and about 252-258 Dur. 642-646 Cam on about a 112lobe.
I'm pulling my 355' out and i have a 406 i'm gathering parts for. I already have a forged crank, rods, no pistons yet? And Canfield 215 heads w/2.08 valves and solid roller springs and a Victor Jr. intake. What i do know is it will be on a direct port kit about a 250hit so i would like to know and hear some opinons on what pistons,compression and if i need to port these heads i know nothing about these heads and what cam these 406's and these heads like.
I'm shooting for a streetable low 10 second car hear. Can i get these heads to work and flow! I was thinking about 12.5 Compression and JE pistons and about 252-258 Dur. 642-646 Cam on about a 112lobe.
What CC are your combustion chambers? I am building a 406 myself, however it isn't going to be as radical as yours. I'm using a forged steel crank, h beam rods, XE284 cam,.541/.544 lift, 240/246 duration on a 110 LSA, ~10:1 compression and a set of worked vortec heads with 1.6 pro magnum roller rockers and a super victor with a 750 carb. If you go that high on the compression, your gonna have to run that expensive gas in it, or your gonna have to pull a ton of timing out of it to run it on the street, and it with a cam that size, it won't be fun to run on the street. You'll have to have a large stall, or if your running a manual transmission you'll have to fight with it. You can get the car into the 10s with a less radical motor if your gonna hit it with the juice, and it will be alot more fun on the street.
I drive a Trex cammed ls1 w a th350 with a manual valve body and 4000 stall daily so it really isn't about the race gas or it being to radical just that it sounds good and will run 10's every pass all day everyday. And of course drive it a around at Turkey Rod and to the local car shows. But i have vortec heads on my 355 with a cam about the size of yours with a 4spd and 4:11 and that little thing ran with vortec heads!! But thinks and tell me what are u shooting for in ur 406?
Staging Lane
Joined: Aug 2006
Posts: 56
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Better get the block done regood if your planin on sprayin over a 200 shot and if its a 4 bolt stock may wanna rethank your plans.In my findings in building a 400 for my ported Brodix track1 heads that the 4 bolt block would be fine unless I started to spray it.Also know a few ppl that had cyn wall probs with spray on the 400s when the motor wasnt stock bore.
Originally Posted by raymond mckinney
I drive a Trex cammed ls1 w a th350 with a manual valve body and 4000 stall daily so it really isn't about the race gas or it being to radical just that it sounds good and will run 10's every pass all day everyday. And of course drive it a around at Turkey Rod and to the local car shows. But i have vortec heads on my 355 with a cam about the size of yours with a 4spd and 4:11 and that little thing ran with vortec heads!! But thinks and tell me what are u shooting for in ur 406?
Here is what my program produced.
I'll have a 4 speed behind my motor and a 3.73 gear. I want a torque monster and I think I achieved my goal.
2 bolt blocks are better, if you must have 4 bolt (500hp+) convert a 2 bolt to splayed main caps. Sonic test, magnuflux before you put money into the block, there are some good blocks still out there, just gotta have'em checked!You can build a low 11/ high 10 406 (depending on the rest of the vehicle weight, gearing , tires ...) without breaking the bank, a decent 200-210 cc intake port head, a "RUNNING CR" of about 8.5-9.0:1, 230's@.050" Hyd flat, a good forged piston preferably flat or dished (Quench, detonation reasons), you don't have to go crazy on bottom end, cast cranks are good upto 550HP when checked properly, go to a decent (again don't have to go crazy) 5.7 rod, Forged crank/rods are a plus (again not neccesary), good balance job and balancer, Hyd roller cam would be a plus as are solid rollers( you must add about 10 degs @.050" to solid type cams when comparing to hyd type cams) but not neccesary. If you add Nitrous the forgings add insurance!
Note: I mentioned "RUNNING CR" of 8.5-9.0:1, what I ment was running compression is what really counts make sure you match your intake closing point with your Static Compression, there're calculators online for figuring this out, pay attention here because it will be the difference between a lazy running engine and a great running eng, 12:1 Comp is as good as 9:1 if both have a running comp ratio of 8.5:1, Intake closing point is what will determine that! Good Luck! Just my .02, feel free to ask any questions!
Note: I mentioned "RUNNING CR" of 8.5-9.0:1, what I ment was running compression is what really counts make sure you match your intake closing point with your Static Compression, there're calculators online for figuring this out, pay attention here because it will be the difference between a lazy running engine and a great running eng, 12:1 Comp is as good as 9:1 if both have a running comp ratio of 8.5:1, Intake closing point is what will determine that! Good Luck! Just my .02, feel free to ask any questions!
