Big Valve 452s. A waste on the street?

[CrewCabCoronet]

Hi all,

in the process of building a street bound 440. already have decided on KB184 pistons to give me around 9.3-1 compression with open chambers. I have the opportunity to get my hands on a set of mildly ported 452s with big 2.14/1.81 valves installed for wayy cheap. On my workbench i currently have a set of 452s that are bone stock but blueprinted at a true 88cc chamber. definitely want this thing to be a stump puller in a moderately heavy car with an automatic, so the cam isnt gonna be radical. would the big valves just hurt me in the end?

 

[HEMI-ITIS]

Those ported heads would be good if you matched the cam to the add'l flow.

 

[CrewCabCoronet]

Those ported heads would be good if you matched the cam to the add'l flow.

I definitely figured it would but my thinking is that I probably wont have enough cam to really take advantage of the big valves. I was thinking of trying something on a tight 108 LSA to really give it some low end grunt, an Isky 270 megacam is something i was looking at. i figured with the quench pistons the lsa wouldn't create any detonation issues and since i dont have power brakes vacumm is not an issue. I could be totally wrong though, but thats why I have this forum.

 

[66Satellite47]

IMO the larger valves can't possibly hurt. "Mildly" ported heads w/2.14/1.81 are a big positive for the increased flow. Seems like cam choice is much more important than the bigger valve size.

 

[CrewCabCoronet]

IMO the larger valves can't possibly hurt. "Mildly" ported heads w/2.14/1.81 are a big positive for the increased flow. Seems like cam choice is much more important than the bigger valve size.

guy told me he used the old MP templates so i assumed anything he did was pretty conservative

 

[66Satellite47]

Ya as I recall those were a real good start and got HP & torque improvement even with small cams. The bigger valves are really NEEDED for big cams & high RPM, but don't hurt for lower power/rpm IMO.

 

[wagonman]

Pretty much the same build I have but with large valve 906s. I used a mild Comp XE268-10. Idle is nice with a slight lope and gobs of torque for a well manered street setup. One thing my machinist did was to check clearance of the quench dome to the head. After decking the block and milling the head it could get close. This also runs on mid grade fuel. Good luck with the build.

 

[CrewCabCoronet]

Pretty much the same build I have but with large valve 906s. I used a mild Comp XE268-10. Idle is nice with a slight lope and gobs of torque for a well manered street setup. One thing my machinist did was to check clearance of the quench dome to the head. After decking the block and milling the head it could get close. This also runs on mid grade fuel. Good luck with the build.

That xtreme energy stick seems to be the hot ticket for alot of street cars. I just had the machine shop take enough off just to true the decks up. hopefully at 88cc i wont have any issues.

 

[lewtot184]

go for it. the biggest issue with the 2.14 valve is the short turn at the pocket. the 452's have a flatter port and this may not be be as big of an issue as the 906's and 915's.

 

[66Satellite47]

Am I correct in my memory that the 452's flat intake port worked just fine in the lower RPM applications with smaller cams compared to the 906 or 915's?

 

[IQ52]

Am I correct in my memory that the 452's flat intake port worked just fine in the lower RPM applications with smaller cams compared to the 906 or 915's?

"the 452's flat intake port worked" is correct. When placed in the rest of the sentence.........no, that is not correct.

 

[66Satellite47]

"the 452's flat intake port worked" is correct. When placed in the rest of the sentence.........no, that is not correct.

OK

 

[IQ52]

go for it. the biggest issue with the 2.14 valve is the short turn at the pocket. the 452's have a flatter port and this may not be be as big of an issue as the 906's and 915's.

Putting a 2.14 valve in the 452 heads helps get a better radius off the seat next to the short turn and results in better low and mid-lift flows.

 

[mentor70]

as i recall, the 452s were the base of the Direct Connection staged heads in the late 70s early 80s, i remember seeing Koffels adds in the rags back in HS selling the worked 452s as the "IT" head to have. the last set of iron heads i had were 452s with 2.14 1.81s and i though they were great.

 

[IQ52]

as i recall, the 452s were the base of the Direct Connection staged heads in the late 70s early 80s, i remember seeing Koffels adds in the rags back in HS selling the worked 452s as the "IT" head to have. the last set of iron heads i had were 452s with 2.14 1.81s and i though they were great.

The Stage IV heads resemble the 452 and the Stage V heads are more like the 906.

 

[747mopar]

I have a set of 452s on my 456 stroker with the same valves and also has had minor port work, according to the flow test they'll support a .550 lift cam.