Honestly don't know now..lol. Maybe confusing it with deck clearance? In my defense I'm no expert and I did mine 4+ years ago.. so memory is not fresh at all. Seemed right at the time.
Another “What Cam and Heads” do I go with….?
- Thread starter 67cuda360
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67cuda360
Well-Known Member
yes that is what I mean with .050 in the hole so .050 clearance from top of the piston at TDC to the top of the deck (deck clearance).
But since the deck height varies widely from the factory that note is pretty useless in real life.
But since the deck height varies widely from the factory that note is pretty useless in real life.
What camshaft? With 8.75 compression too much cam will be a power killer. That's not to say an 8.75 motor cannot scream.
67cuda360
Well-Known Member
The cam specs are listed in the image. Also included is static compression, dynamic compression and the cranking psi based on the cam specs.
Those positive numbers are correct for a dished piston. You use negative numbers for domed pistons.Getting old.. cannot read the specs in the photo... lol.
I looked up the specs at Summit. Silv-O-Lite Hypereutectic Pistons 1279HC.030 .
The specs. at Summit indeed says:
"Piston Head Volume (cc): +7.50cc"
But also has the following note at the bottom of the spec. sheet:
"Notes: 3.130 inch diameter, 0.050 inch deep recessed piston head."
I don't see how you get a positive piston head volume with a .050 recessed "dished" piston head?
Maybe one of the smart fellas here can bring me up to speed.
*** EDIT***
Just wanted to add even the compression calculator states to use - for dome and + for dished pistons.
I come up with 8.72 static and 7.59 dynamic. Pretty close to what you have. I'd leave it right there. That's dead perfect for a street engine.
67cuda360
Well-Known Member
Thanks. So you think that cam would be a good match for the 3.23 gear with trickflow heads and 1.5 prw rockers and would smoke some tires down low? Don’t think there is a need to go to 1.6 rockers with the added stresses that creates although the roller cam can probably handle it.
Not the 1.6 no, not in my opinion. That cam has a lot of lift already. Is it a Howards grind? They're known for using more lift per duration. I like that. Yeah it should heat um up good. I'd go with a custom converter that'll flash to about 3600. Tell them you want it tight so it'll cruise around town like a stocker.
67cuda360
Well-Known Member
The cam i looked up was from hughes. But i am open to alternatives.
Seems like a goodun. Go for it.
Like any auto combo, converter will be primary key to how things work.
From experience and you can look at Holdeners dyno stuff, check out what little change there is down low between cams. If they print a 2500 number, great.
Short duration less lift, better dynamic compression BUT more lift and some more duration fills the cylinder better, better BANG
Until you start breaching the 235 @ .050... meh...
From experience and you can look at Holdeners dyno stuff, check out what little change there is down low between cams. If they print a 2500 number, great.
Short duration less lift, better dynamic compression BUT more lift and some more duration fills the cylinder better, better BANG
Until you start breaching the 235 @ .050... meh...
TXOval
340 stroked to 416
If buying the TF heads…Harland Sharp sells rockers specifically for them.
In my experience, Mike at B3 has said the PRW’s are the worst for geometry.
I’m currently installing a HOWARDS CAM 710665-10 in my 416. If you don’t mind the cost of a roller cam, I would go that route.
In my experience, Mike at B3 has said the PRW’s are the worst for geometry.
I’m currently installing a HOWARDS CAM 710665-10 in my 416. If you don’t mind the cost of a roller cam, I would go that route.
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67cuda360
Well-Known Member
That is interesting, I had started a thread about rockers and it seems for a street engine steel rockers are preferred. Maybe you are thinking of the older style PRW? That one seemed to have some clearance issues regarding springs retainer etc.
I read a lot of threads saying that people use the PRW on trick flows with great success and that a lot of them have bought them from B3 racing with the correction kit. But I'll be sure to call him and see what he suggests is best when the time comes to pull the trigger so to speak.
LJ67barracuda340
Well-Known Member
I used the 222/226 hyd roller from Hughs. Edel perf RPM heads, Hughs 1.6 roller rockers (.555 lift) Zero deck, 10.2 cr, .039" h gask, 185# cranking p. in my 340.
Thing makes lots of torque down low which is what I was after. 5 speed manual, 3.23 rear.
I wouldn't change a thing unless you wanted the cruise nite idle. With the 1.6 rockers you have to work on the custom push rod passages in the heads.
Oh, and it runs on 91 but I've tried a 1/4 tank of 87 and it's ok if you dont push it. I run 91 all the time though. I'm at 300ft. I feel with the 3500 torque converter you are waisting the bottom end that cam makes. JMO
hope that helps
Thing makes lots of torque down low which is what I was after. 5 speed manual, 3.23 rear.
I wouldn't change a thing unless you wanted the cruise nite idle. With the 1.6 rockers you have to work on the custom push rod passages in the heads.
Oh, and it runs on 91 but I've tried a 1/4 tank of 87 and it's ok if you dont push it. I run 91 all the time though. I'm at 300ft. I feel with the 3500 torque converter you are waisting the bottom end that cam makes. JMO
hope that helps
67cuda360
Well-Known Member
Wow, that seems like a pretty good comparison. I was concerned about the lack of "cruise night idle" lol, I have to say I am shallow enough to enjoy the overlap "lopey" sound.
I really like the idea of going roller (less concern with wiping out lobes, and faster ramps etc.) but I think it is going to be between the (SER2226ALN-10) 222/226 hyd. roller you mention and the (STL3438AS-8) 234/238 solid flat tappet cam. Both cams say they work well with stock to mild converter and 3.23+ gears and dynamic compression and cranking pressures seem very, very close between the 2. The Solid FT will sound more "lopey".
What lifters and Springs did you use on your roller?
TXOval
340 stroked to 416
I should have clarified…PRW on Speedmaster heads…sorry about that
4eighteener
Well-Known Member
I would say if you can afford it, go with the roller cam for peace of mind. Nothing worse after installing an engine than yanking it back out because the cam got wiped and having to re-clean every passage of the metal flake oil.
Episodes of both Holden and Engine Masters show a good set of heads make a smaller cam more effective than it would be with a lesser head.
I have the Howard's version of that hughes cam that lj67baracuda340 in my daily driver truck which has a 221/225 on a 112 with slightly less lift with trickflow heads and prw1.6 and 3.23 rear.
No idle worth bragging about, but it is a strong motor and a good compromise
67cuda360
Well-Known Member
How are the prw rocker with the trickflow any noise/concerns?
4eighteener
Well-Known Member
No, not at all. I just passed 10k miles since the rebuild with no issues, just oil changes.
LJ67barracuda340
Well-Known Member
There's two RPM heads. I used the one with the Edelbrock roller springs (60779) I think, they're very close to recommended. Hughes Hyd roller lifters are on it. I agree about the oil but the fast ramps make it breath and thats what you said you want. You can hear my cam lobe, it just doesn't bring people running to look, lol. I drive the car and not so much go to shows.
JMO if you take the lash out of the duration on the solid flat, how close do you get to the roller spec? and I think the roller will have faster action. I also use a 950cfm EFI throttle body, it's all about breathing.
That thing will be a puppy dog idle with the 222 roller cam
I think roller cams are more of a fix for the goberment making zinc oils unusable in catalytic cars. Non rollers valve trains are a lot lighter and can perform quite well. I could be wrong. Just spit balling here.
4eighteener
Well-Known Member
If I had access to a dyno, or a engine stand to run and break an engine in on, I would be tempted try flat tappets.
Or, if I had bought lifters and had them reground and paired up with a quality cam, say from oregon cam with correct taper.
For now I just push the easy button and put that money towards a roller set up and have few concerns
Or, if I had bought lifters and had them reground and paired up with a quality cam, say from oregon cam with correct taper.
For now I just push the easy button and put that money towards a roller set up and have few concerns
67cuda360
Well-Known Member
Thanks for all the feedback. If i am changing the cam anyway it is probably the best time to make it less prone to issues and enjoy the benefit of more aggressive ramps etc.
So roller should be top of my list. Any other special things needed to run a roller in the LA block. I’ll do some research but I assume pushrods of course, the lifters, distributor gear needs to be bronze i’d imagine. Anything else needed such as cam buttons or retaining plates like some makes?
So roller should be top of my list. Any other special things needed to run a roller in the LA block. I’ll do some research but I assume pushrods of course, the lifters, distributor gear needs to be bronze i’d imagine. Anything else needed such as cam buttons or retaining plates like some makes?
I’d pay up for a melonized steel distributor gear if you’re gonna be doing regular street driving or putting a lot of miles on it.
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