James

Since I finally decided to tame down the 509 I had in my 69 I decided to make a few changes this time around. First off this will be a street performance motor not a race motor. Also I have couple of things that kind of limit what I can and can't do. I went ahead and purchased an Eagle rotating kit for it with a 4.250" crank to make it into a 540. I also ordered the crank with their “ESP Armor” finish and it looks to be a nice piece. All of the journals were dead on spec. The pistons that came in the rotating kit are supposed to get me in the ball park of around 10:1 with an 118CC head. I still need to purchase the heads and run the numbers to get the exact compression and finish the final block work. My goal is to build low maintenance high longevity 540 cubic inch big block running a hydraulic roller cam. One thing that limits me is I want to replace the cast iron Merlin Rectangle port heads I had on the 509 with a set of Aluminum heads. I had to have the driver’s side header modified in order for it to work with these heads a number of years ago. I really do not want to have to go through that again so I think I'm just going to purchase a set of Merlin III Aluminum heads which are supposed to have the same specs as the cast iron Merlin’s I currently have. So basically what I'm looking for are opinions or combinations you guys have used on motors like this and what you would recommend for a dependable Hydraulic Roller cam that will get me 550 to 600HP. Also what are your opinions on the heads as far as would I be better to go with 310CC runner vs. a 350CC runner since the motor is not going to be a high RPM motor? Thanks.

burners

I recommend looking up Jim Moore (427Hotrod). He's the man when it comes to big inch big blocks. Of course he may have you running 8 second quarters before it's all done but he certainly knows his stuff and he's a great guy.

James

Excellent!! I have followed a number of threads he has been involved with so hopefully he will chime in. Thanks.

69ttop502

Most all of the good aftermarket aluminum heads have a raised exhaust port as your Merlins must have had. So you have already done all the hard work to your headers. For your application, the AFR 305 or fully cnc'd 315 would be my choice. The 315's would give you room to grow later if you wanted to spin it a little more. As it is in big blocks and hydraulic cams, it is tough to get them to rpm so the hydro roller will limit you to 5500-6000 rpm. I would say to consider a solid flat tappet instead. Can still spin it a little and with the edm lifters and good oil, are low maintainence. I have a solid flat in my 502 with the AFR heads and it is a great, low maintainence combo. 540's really tame down a cam so a cam that may seem wild in a smaller motor will be real docile in your motor. And with good heads, the less cam you need. In my thinking though, it is still fun to spin the motor a little. Jim will definitely steer you right.

You should be able to meet your hp goals without breaking a sweat or more than a 5500 rpm peak. My 502 uses AFR 315's, solid flat tappet with 258 @ .050 with .615 lift on a 108 LSA. I have a Holley Strip Dominator intake with an 1000 HP, and 10 to 1 compression. With this combo I made 614 horsepower on a very conservative dyno at 6100 rpm's and believe me this cam is tame, even with the 108 lsa. In addition I am running a 1.8 intake rocker so lift is a little higher than spec.

TheycallmeDave

Boy, would i ever love a 540 in my 1970 BB Vette. I opted for a 468 with roller cam, roller rockers, and roller lifters. Went with a Lunati Cam for street use 2500 to 6000 rpms (232/242 dur. @ .050" / .553 and .595 lift) . It was a screamer ...but what REALLY made a huge difference was when i put on a new Mighty Demon 800 cfm , annular, mech. secs..Carb . I then had it tuned by a real professional who recurved the Distributor for maximum low end torque and tweaked the Carb and Timing. It was the best $400 i ever spent --- a day and night difference ; a real torque Monster . In hindsight, i should have gone with a stroker kit to make it a 496 ... but what I have is scary enough. With your 540 , youll be looking at 600 gross h.p. **minimum and about the same in gross torque. Give us an update once you get it all running good.

gkull

First of all an old big block chevy can't be made into a 540. Something I'm unclear about the 509 unless it's a more modern 502 with a larger bore.

going from 509 to 540 is a minor change in % of ci. I also could not imagine even a 400 ci motor with cam as tiny as 232/242

TheycallmeDave

Im aware that you cant get 540 out of a 454 block ; I was just saying how id like to own a 540 motor -- sorry if i didnt make it more clearer. As for my cam of 232/242 on 112 degree centers , it is a very good street cam that starts coming in around 2500 rpm and with my goal of maximum low end torque for street only , it is absolutely ideal ; when selecting a Cam, you have to look at where your car is going to be most of the time on the RPM scale...and for street only driving, mine seldom sees 4500 rpm.

L88Plus

If all you're looking for is 600hp, you're gonna have to pull a plug wire or two loose
Don't restrict yourself with Merlin heads - there are MUCH better heads available for about the same money. In testing, they barely beat GM's own rectangle port heads. I'd check out AFR, Dart and Brodix.

427Hotrod

Sorry I'm late to the party. I missed your PM!

540's are great...555's are even better, but since you've already got the pistons I'm assuming the bores are still clean and just a good TQ plate honing will take care of them. I'm assuming the pistons have a small dome on them? Any idea who made them?

As Gary mentioned...there are heads a LOT better than the Merlins. I used a set of the iron ovals on my 427 but they had a lot of flowbench time and port work to really flow. All of the 3 mentioned will be great. The AFR 315's won't hold you back at the RPM range you're in, but I'd still pick the 335's. The 555" we just did with DART 335's was great. Plus we didn't have any valvetrain geometry issues like the AFR's seem to have most of the time. Out of the box the heads were great. I spent a little time doing some port cleanup, but nothing dramatic. They made well over 700 ft lbs of TQ and had fantastic throttle response. They carried RPM out past 7200+ easily when we had the bigger cams in it. I don't believe in little heads on big motors.

We ran a Hyd roller, a solid flat tappet and a solid roller in it. The custom Hyd roller I spec'd was a good one. We peaked HP at 6100-6200 RPM or so and it pulled easily to 6500-6700 RPM. After 6800 rpm it was dropping off pretty fast. I picked that RPM for peak HP so we could extend shift points to around 6500 and actually use all the power at 6200 with no valve float worries. The solid flat tappet made the same peak HP...but was down in power at low RPM...but it also could spin past 7000 rpm without breaking a sweat. Wait 'till you see what the flat tappet did with a Dominator and big intake!

Whatever you do, don't scrimp on intake manifold size. Bigger is better even with the hyd roller cams. You can tune for manners with the big intake..but when you decide to stuff your foot in it there is LOTS more power with a good intake. Don't starve it on carb either. Even the mildest version loved the 1150 Dominator, though we also tested with a Holley HP 1000 that did well.

JIM

James

Thanks for the reply and help Jim. Yes the bores cleaned up just fine with a few passes on the honing machine with a torque plate in place. My biggest issue with switching heads is making sure I do not have to modify my Hooker Headers again. After I had them modified the last time around I had them ceramic coated and then sprayed with HPC’s black hyper coat finish. Might you know of anyone running the Dart 335’s on a C3 with Hookers side exhaust setup? As far as the cam is concerned I ran a solid roller in the 509 and never had any issues. I still have the cam and lifters and they have fairly low mileage on them so I could re-use the lifters if I wanted to. I just thought I would switch to hydraulic roller this time around just to make things even simpler. I have Jesel shaft mounted rockers and they really helped keep the valve train in spec and I plan to use them. For the intake and carburetor I was hoping to re-use a Weiand Stealth Dual Plane intake and Holley 1000HP I have because they both mate to the L88 air cleaner and cold air box I have mounted to the L88 hood that is on the car. The pistons that came in the rotating kit were supposed to SRP pistons but they ended up being Mahle Forged 4032 High Silicone Low Expansion Aluminum Alloy pistons. I have always used SRP in the past but from everything I have read the Mahle is supposed to be a pretty decent piston manufacturer. The pistons are all coated with their proprietary Grafal anti-friction coating which I do not know very much about either. Any opinions on Mahle pistons I would be interested to hear too?

427Hotrod

First, the Mahle's are excellent pistons. You'll be fine with them. I think they usually have a 13cc dome vs a 10cc one on the SRP's so you will get a hair more compression if I'm right.

The 555" we built with the Darts is installed in Doug *Snowman*'s C-3 with Hooker sidepipe headers. Now he does have Steeroids on it, but he didn't have to mess with them. The Dart heads are raised .300". The Merlins say they are in stock locations, but it seems like the plugs are angled differently and that's where it got tight...especially around #1 and #3 plugs. You might check the threads on his car or send him a note. I'm sure he can fill you in. His were coated too and he definitely didn't want to mess with them!

I have Brodix heads and my ports are raised .600". I'm using Hooker under car 2-1/8" headers. On my car the raised ports actually made them fit better than they did with stock heads. I have one dimple by the steering box, but nothing crazy.

We had great luck with an ancient Edelbrock C-454 dual plane and a Dominator. The Stealth is also a big runner intake so it won't be bad, but it will hurt things as you go above 6000 rpm. Any of the big single planes will run away from this stuff if you go 6500+ rpm with good heads..and still make more power at 4000 rpm too.

Need to give it serious airflow!

JIM

James

Sounds good Jim. The Merlin cast iron heads I was using had the exhaust ports raised .250. I would imagine the .300 on the Darts would most likely not casue me any issues. I take it the Dart heads you are talking about are the Pro 1 series? Just poking around I seem to only see them available in 310CC, 325CC, 345CC & 355CC intake runners. I do not see a 335CC head. Looks like I have more research to do.

427Hotrod

Yes, the 335 and 355's are the Pro 1 CNC heads and are killer.

http://www.dartheads.com/products/cy...cnc-heads.html

I always thought the Merlins were raised too...but their website says they are stock. But there is a lot of bad info on their site where they repeat the same info different ways on the same page- so take it with a grain of salt. It's been a long time since I messed with any of them so you are a lot closer to the correct answer than I am. Either way, they aren't big power makers by any stretch unless you work on them some.

Good luck...there's a LOT of power in those heads! That's where ALL the good power is!

JIM

vettesbydesign

James....before you order...please keep me in mind.I can get the Pro1 CNC assembled heads for $1970.00 each,and split the shipping cost w/you,and the bare of the same for $1490.00 each,and split the shipping w/you.These are in stock,and will be on your door step in a couple days from order date.
I also,carry all the cams(flat tappet,Hyd./Sld rollers),all the best gaskets,intakes,carbs,whatever,and will make sure that I beat everyone's pricing.
That car was already a BEAST!This outta be fun,and you have the right guys here helping you w/your parts list.
Kevin