452 heads on a 361?

[jmbass98]

Couple pairs of 452 heads near me in good condition for what seems to be a decent price (180-200 USD). Are these an improvement over the stock 361 heads? '66 Charger. Will they bolt on without modification if so?

 

[Don Frelier]

Probably not they have much larger chamber volume.
Yes they will bolt right on.

 

[zyzzyx]

I believe the open chamber heads will bolt on but if it's a 66 engine the compression ratio
will be way low. Hopefully someone else will chime in to reinforce this? The pistons on a
66 are further down the hole.

 

[RemCharger]

Never worked on a small-bore before.. not sure how the ex valve to cyl wall clearance would be like.

 

[RemCharger]

Yep low compression is right. Id stick with 516s

 

[Curiousyellow71]

Well...I am not a 516 fan but I am fond of 452s. I don't think I would ever use a 516 unless I was going for originality. The guys are right 452s w be lower compression. 84cc to 90cc is about half a point lower. I would have a machine shop shave .050 off the 452s and run them. If they are both stock it's a trade off.

 

[Jerry Hall]

Find you some 915 's, IMO, or stick with the 516's.

 

[qkcuda]

I just had the 516's on my 66 361 redone. We cut them .020 and cc'd them. They came in at 75cc's. The pistons were .065 below deck. I used a .040 composition head gasket and compression came in right at 8.5:1. The last set of 452's I had were almost 90cc's. That would severely drop your compression ratio.

 

[66Satellite47]

I did several sets of 516's for moderate 440's. I did basic bowl porting. One set used the stock size valves, the other two sets used the 1.74 exhausts. The cams were similar to the .480 ish Purple Stripe cams. All in '68 or 69 Chargers. Ran good, high 12's to 13 teens in the late '70's - early '80's.
I think the larger valve would work fine in the 361. My 426 Street Wedge used 906's on the 4.28" bore with no problem.
The 452's do have big chambers, do the math & see where the CR comes out.

 

[R413]

516 heads are good. I use them often on the older engines.

What Kind of driving are you doing with the car?

If you put them on a stock engine the performance and gas mileage will go down. It’s all in the chamber as stated above.

 

[Nate S]

I wouldn’t bother. The 452’s flow better and flow will gain more than compression generally. In the case of a 361 you already have a big block head on a small block displacement. Keep what little compression it has.

 

[PRHeads]

I can’t see it being a worthwhile swap for what most people would ever do with a 361(let’s call it 400hp or less).
The 361 only has a 4.125” bore(it’s like a small bore 383), so I’m not sure how much room there would be for the 1.74 ex valve.
It might even need a little notching.
I’d def test fit it before assuming it’s good to go.

 

[66Satellite47]

I forgot the bore was only 4.125. Duh! The big exhaust valves probably wouldn't fit without notching the tops of the bores. I still say that the 516 is just fine with a moderate cam and a little pocket porting & good valve job.

 

[R413]

516 heads really are good, they get a bad rap. If you have a Stock restoration or a mild street driven cruiser they will be great.

My 516 head story: I had a 67 440 350 horse engine. All stock ran sweet. Installed an unknown cam from a friends engine that sounded like a 440 magnum cam, smooth idle with 18” of vacuum, slight rumble out the tailpipes.
933 mopar perf valve springs
750 AVS
Magnum Exhaust manifolds
3.23 SG in a 67 Belvedere.

It was tons of fun. It was a daily driver. I put 3000 miles on it. Would run Consistent 14.20 @ 96 with street tires feathering the gas. 5200 rpm shifts is what it liked.

I decided to “upgrade” to 915 heads with 1.74 exhaust valves. It ran and drove the same. The car didn’t pick up anything at the track either. 14.20 @ 96

Conclusion: with a stock type cam and gearing this car ran just as hard with 1.60 small valve 516 heads.

 

[Challenger340]

"Good" is relative to the application.... or airflow demands of the Engine ?

a 361 ?
stick with the 516's and small Exhaust Valve.

 

[R413]

"Good" is relative to the application.... or airflow demands of the Engine ?

a 361 ?
stick with the 516's and small Exhaust Valve.

Yes Exactly it’s all about what you are doing with the car. That’s why I posted my example, no change at low 14’s on a 440 street car. So a smaller BB don’t need them either.