Greetings all, would like feedback on the following combo.
70 chevelle street strip intentions, 4spd, 3.73, 540 ci w/flat top pistons (9.5/1 w 119CC)

Already own Merlin Cast Iron Rectangular port 310CC 2.19I and 1.88E heads (original Merlin I's)

Enough flow or should I spend more $ for bigger heads?

Cam selection roller solid or roller flat tappet, any suggestions

...70 chevelle street strip intentions, 4spd, 3.73, 540 ci w/flat top pistons (9.5/1 w 119CC

First off...How much street & how much strip ??

One thing to consider...that "4 spd"...what kind? Chances are it's not gonna last too long behind a 540.
For a mild 540, sure, the already-in-hand Merlins will do fine.
But with only a 310cc intake, I'd suggest staying away from a solid roller and the higher rpm advantages of those cams. The flow to support that just not gonna be there.
Are you sure a 9.5 CR is possible with a flat top piston and 119cc combustion chambers ?

Yes, I know the 4spd is going to be the weak link and will probably lead to the need for replacement.

The compression doesn't seem right by traditional thought, but the bigger swept volume into the 119CC chambers does works out to 9.5 to 1.

I guess I have one of two directions to go with this, either a mild 540 with the merlins and flat tappet solid or spend the extra $ for bigger heads and cam.

I guess the question would be if anyone has had any expierience with the smaller 310cc heads on this big of a motor and and what I could expect with that and a cam optimized for that combination.

Pick a great UD Hyd roller or cammotion hyd roller (on billet cores!!) and "set it and forget it"! Would make for a killer, low maint, street-strip ride. My guess is you won't notice the 25 or 30hp max difference between that and a solid roller given the heads. My SR hasn't moved a thousandth since it was installed (5k miles..), but I have a girdle and crower SS rockers, and a very detail oriented head setup guy...

JMHO

matt

junk the merlin head, if you want a cheap cast iron, go with the new cast iron DART iron eagle

Fresh off the dyno, almost identical setup, made 580HP @5800 and 636Ft.Lbs. @ 4100. C.R. was slightly lower at 9.2:1. The heads worked OK with minimum amount of porting and same valve sizes. Used 230 x 236 - .560 lift Comp Cams Hyd. Retro-fit #11-451-8, along with a 4500 carb. Thanks, Gary in N.Y.

Hmmmm.....

We had a 9.2:1 CR 540 dynoed by a customer about 8 or so years ago.
The cam was an UltraDyne 288/296HR14, 236/244 at .050", .600"/.600" valve lift, and 114 LSA. It idled about 850---No, I don't remember the vacuum!--and ran on 87-octane.
At 1500 it had 505 ftlbs of torque.
At 3000 it had 555 ftlbs of torque.
At 4000 it had 599 ftlbs of torque.
At 4500 it had 625 ftlbs of torque.
At 5000 it had 625 ftlbs of torque.
At 5500 it had 594 ft lbs of torque.
At 5400 it had 630 BHP.......
He had 2 of these engines in his boat......

The VooDoos include a 231/239 with .600"/.600" valve lift, and a 241/249 with .625/.625" valve lift. The larger cam would work on a 114 LSA just fine.....

UDHarold

BTW, Please remember that different dynos read different numbers, and the only comparison is between 2 cams on the same dyno, preferrably within a day or two apart.

I have the same question: I will be getting into a winter project on a '72 Chevelle. My dream is to build a killer street strip car thatt runs on pump gas. Current build engine BN which is out of car:
Merlin II 540
Merlin 119cc 310cc rec port heads 2.25 I, 1.88 E, 1.550” Dual 225# springs, .700 lift
9.3:1 CR
World products Merlin single plane intake
Schneider Racing solid Roller Cam .646 lift, 258I /272E duration @ .050 lift, lobe sep. 112 (trying to help the bad E flow of heads)
3500 stall TCI
TH 400 built to 1000HP
Holley 1000CFM
Lemon cutom headers 2.25" primarys with 4" collectors
4.56 posi 12 bolt rear end (I may change this and or install US gear 30% overdrive for cruising)
I run the numbers on this setup on Dyno 2000 and get 586HP @5500 and 621ftlb @ 4500
I think I can get a lot better with a new cam and heads
I was looking at AFR and have not settled on which would work the best I have a new COMP Cam 270I 280E @ 0.050 and .714I and .710E laying around But do not know if the 110 LCA is good for a 540.
I am looking for any opinions on the best street/strip setup for the 540 that can run on pump gas. I want to plan before I put the engine back in the car.
thanks in advance.

When working with 540s, or any BBC engine with a 4.250" stroke, think of LSAs of 110 about like 108s in a 454, 112s similar to 110s in a 454, and 114s as acting like 112s in a 454. This is not perfect gospel, but very close.

UDHarold

I have the same question: I will be getting into a winter project on a '72 Chevelle. My dream is to build a killer street strip car thatt runs on pump gas. Current build engine BN which is out of car:
Merlin II 540
Merlin 119cc 310cc rec port heads 2.25 I, 1.88 E, 1.550” Dual 225# springs, .700 lift
9.3:1 CR
World products Merlin single plane intake
Schneider Racing solid Roller Cam .646 lift, 258I /272E duration @ .050 lift, lobe sep. 112 (trying to help the bad E flow of heads)
3500 stall TCI
TH 400 built to 1000HP
Holley 1000CFM
Lemon cutom headers 2.25" primarys with 4" collectors
4.56 posi 12 bolt rear end (I may change this and or install US gear 30% overdrive for cruising)
I run the numbers on this setup on Dyno 2000 and get 586HP @5500 and 621ftlb @ 4500
I think I can get a lot better with a new cam and heads
I was looking at AFR and have not settled on which would work the best I have a new COMP Cam 270I 280E @ 0.050 and .714I and .710E laying around But do not know if the 110 LCA is good for a 540.
I am looking for any opinions on the best street/strip setup for the 540 that can run on pump gas. I want to plan before I put the engine back in the car.
thanks in advance.
=
The 270/280 is a bit long for a 9.3 street engine & I think the headers are on the large side too. Why the 2 1/4" primaries?

Also if you are planning on AFR's you do not want 10 degrees of split on the cam with a good exhaust system.
More like 4 or possibly 6 degrees max.
Something in the 264/268 or 268/270-272 with as much lift as you are comfortable with should work pretty fair & my preference would be on a 112.

With this & the AFR's you are looking at about 800HP on an honest dyno

If you are considering AFR heads email me & I can probably save you a dollar or two on them, ;)

Scott,
You didn't answer the question about street vs. strip. If you are gonna run it at the strip....with traction, ditch the 4 speed, cause you will break it. Unless you plan to spend $4K on a G-force with a clutch to match....oh, and a rear better than a 12 bolt.
If it's a street car, it puzzles me why you need a 540.....unless it's what you have to have. Makes no sense to me, when even a decent 454 won't get traction with street rubber.
But then, we do get to build what we want!
So, if you want the best simple combo that makes GOOD, no GREAT power, get some better heads. Fergit the Merlins. Make sure you have a cam that matches....and don't worry about "only" 9.5:1 CR. I have a bit less and it's working just finefor me with a 498" engine. Practically a small block by todays standards.....
Or, stick with the Merlins and a cam to match and lose sleep at night because you left HP on the table.......do you hate me yet?

Bowtieman427

Define "killer" street strip car. With an ET goal in mind, folks here will give you a "**** and fall back in it" combo that will do exactly what you want. There are so many good parts available now, it's almost easy....well not quite, but you know what I mean.

One last thing, I wish you guys would support your local favorite machinest on these engines instead of running to Shaffriof. These guys know their stuff, and will back up their work w/o having to argue over the phone and end up shipping a 700 lb lead weight back to the east coast. Your local guy will appreciate the business. Unless you live in a small town w/o any good machine shop services that is.........

Ron