440 Heads Rebuild

[LR1970]

Hi, I'm going to rebuild my heads soon. I am building a pretty mild 440.

750 holley, RPM intake
268/280 duration cam
Headers, 2.5 inch system
match port the intake and heads

I have a set of new oversize valves I can use, will they be an over kill or should I just buy a new standard size set.

If I buy a standard size set will I buy the undercut stems?

Thank you

Leigh

 

[Badvert65]

Larger valves are a good thing for factory 440 heads but it will take machine work to use them. When I installed them (some years back), besides having the machine work to fit the valves, it was recommended that the guides be replaced as well. (With a 3 angle valve job, the valve sealing edge is narrow and good guides are critical to a good valve seal). So be prepared for additional costs.

 

[383man]

Honestly in a mild 440 like that the larger valve wont help much if any at all. If you plan to step it up down the road then you could spend the money but as was said it will cost money to put larger valve seats in and work the heads as you want to be sure and have the valve area unshrouded also. And consider if you step it up later you may buy aluminum heads so you have to decide if its worth it to you. Myself on your combo I would just use the stock size valves. Ron

 

[IQ52]

torque and horsepower 2.08/1.74 valves vs 2.14/1.81

440, About 10:1 if I remember correctly, RPM intake, mildly ported 346 heads, XE285HL cam.

RPM...........TQ/HP w/ 2.08/1.74 valves............TQ/HP w/ 2.14/1.81

3100.....................439/259.................................442/261
3200.....................450/274.................................455/277
3300.....................477/300.................................477/300
3400.....................491/318.................................483/313
3500.....................495/330.................................493/329
3600.....................499/342.................................501/343
3700.....................505/356.................................503/355
3800.....................502/363.................................507/367
3900.....................492/365.................................510/379
4000.....................490/373.................................511/389
4100.....................486/379.................................505/394
4200.....................489/391.................................504/403
4300.....................493/403.................................502/411
4400.....................493/413.................................496/415
4500.....................488/418.................................494/423
4600.....................481/421.................................487/426
4700.....................482/432.................................485/434
4800.....................481/439.................................483/441
4900.....................488/455.................................489/456
5000.....................488/465.................................493/469
5100.....................478/464.................................493/479
5200.....................474/470.................................493/488
5300.....................487/491.................................486/490
5400.....................490/504.................................486/500
5500.....................470/492.................................492/516
5600.....................464/494.................................486/518
5700.....................453/492.................................472/512

Soooo, I guess if you are going to stay under 3700 rpm they won't do much good. But beyond that they might be worth it.

 

[67 coronet]

buying new valves vs cutting new seats will be so close in cost you might as well use the ones you got.they may only build a couple more horse,but wont slow you down any.

 

[Cranky]

I think IQ showed what they can do....if you already have em, use em.

 

[Meep-Meep]

May not be an earth shattering difference between 2.14 / 1.81 vs. 2.08 / 1.74 so I'd weight the cost associated with the installation.

 

[383man]

440, About 10:1 if I remember correctly, RPM intake, mildly ported 346 heads, XE285HL cam.

RPM...........TQ/HP w/ 2.08/1.74 valves............TQ/HP w/ 2.14/1.81

3100.....................439/259.................................442/261
3200.....................450/274.................................455/277
3300.....................477/300.................................477/300
3400.....................491/318.................................483/313
3500.....................495/330.................................493/329
3600.....................499/342.................................501/343
3700.....................505/356.................................503/355
3800.....................502/363.................................507/367
3900.....................492/365.................................510/379
4000.....................490/373.................................511/389
4100.....................486/379.................................505/394
4200.....................489/391.................................504/403
4300.....................493/403.................................502/411
4400.....................493/413.................................496/415
4500.....................488/418.................................494/423
4600.....................481/421.................................487/426
4700.....................482/432.................................485/434
4800.....................481/439.................................483/441
4900.....................488/455.................................489/456
5000.....................488/465.................................493/469
5100.....................478/464.................................493/479
5200.....................474/470.................................493/488
5300.....................487/491.................................486/490
5400.....................490/504.................................486/500
5500.....................470/492.................................492/516
5600.....................464/494.................................486/518
5700.....................453/492.................................472/512

Soooo, I guess if you are going to stay under 3700 rpm they won't do much good. But beyond that they might be worth it.

This dynoed eng is making a bit more HP then I am guessing his would as I would have guessed his eng to be around 400 to 450 HP depending of course on many things not listed like if he uses headers or not. Course as you go up in HP the larger valves will help more. Will it be enough on his eng to be worth it ??

This dynoed engines peak hp is 518 with the large valves and 504 without and peak torque is 511 with large valves to 504 and at different rpm's. Even at this HP level its 14 more peak hp and 7 more peak torque. Course it would depend on how the HP and torque curves work with his setup but I dont see his eng getting near 500 hp so it may be even less help with the larger valves.

But if you are going to spend money on the heads and have a valve job done anyway then you can weigh out the difference of how much more they will charge to put the larger seats and valves in and do all the machine work as you did say you have the valves already right ? As was said it cant hurt I just feel it wont help much on your combo. But like others said if your planning on spending so much on the heads for atleast a valve job find out if its not to much more and if you can afford it to go with the larger valves. Course they will have to port and work the bowls with the larger valves as I put the 2.14 and 1.81 valves in my old 440's 906 heads myself and I know how much work it involves but I did want to port my 906 heads anyway. Hopefully they wont charge you more then you can afford since you have the valves because if you cant afford their price you would have to buy the stock size valves since you dont have them right ? So it may be in your best interest to just have the bigger valves done. Now you could always sell the heads and buy Stealths heads as that would be a nice step for you if its in your budget. Good luck on whichever you decide is best for you. Ron

 

[LR1970]

Thanks for the reply's guys. I was really asking if the OS valves will decrease performance on a mild engine. I already have the set of valves so it would be just one thing less to buy. And I have to install the valve inserts for unleaded petrol use so I have to spend money there anyway.

Thanks guys

Leigh