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427 vs 438 ci

4584 Views 13 Replies 10 Participants Last post by  torino501
ive decides to ditch the 347 base stroker,im contemplateing the speedomotive 438 with the dart iron eagle block all forged internals,ive already got the afr 205,if im going to spend 5800 dollars on a short block might as well go bigger,BUT.... im torn between a 427 or the 438,both will have the 4.125 bore but the stroke im couriouse about,427 will have a 4.00 stroke 438 will have a 4.10 stroke and a 1.60 rod ratio, or 1.68,all these numbers i cant remember.veh will be s/c will have the holley roots 174 for now,probly all i will get out of it on the big motors is about 7-8 lbs of boost "MAX" with the smallest pulley avail,will go with the ati after my wallet has healed up i already have the head and the s/c,thganks for any input/out put guys.
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Sounds like the same question between a 331 and a 347; Rod ratio.
If the thoery holds, the smaller number won't be as hard on the pistons with side pressure and live longer.
What is the difference in overall piston skirt length and in either of them, or both, does the oil ring cross the pin?
you have to ask yourself....Do I want a good rod ratio or do I want the extra 40 lb-ft of torque from the cubic inches?

Pretty simple answer.
yeah.....???? i want my cake and eat it to,im realy leaning toward the 427 ,seems ill have more piston material to play with to get the comp ratio were i want it,and not have to worry about cooking a piston due to it being to thin\ between the dish and the bottom of the piston,also gets the wrist pin further away from the oil ring,and looks like a better rod ratio
I think I'd lean that way too, for the same reasons
I would build the 427. My reason is that it is a Ford number and you get to tell others " it's got a 427 inch motor" Sounds so cool!
Heck, put a 4.250 stroke in it and move on.
With that block I'd use all the cubes I could. The cranks should cost the same. Why leave free power on the table?

Thin piston on a blower motor. I understand some concern. Afraid of the rod ratio? Not me. Look around at some factory engines and their crappy rod ratios. Many of those engines go well over 200,000 miles. How long do you think it'll take you to put 50k on that blown stroker? I doubt this is your driver. I'd bet a looooong time. That would be a long time you could be making more power. How much you need is up to you. Just my opinion.

You can call it a 427. It's just kind of a let down when you pop the hood and it's not an FE.

<font size=-1>[ This Message was edited by: 289nate on 3/1/06 5:17pm ]</font>
If it were me I d put the most cubes possible while maintianing reliability, and I would call it a 351 no matter how big it actually was.
Is there a question?
435142506250 4.250" internal 3.000"

Can you say 454? But 205's will be a bit small...
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well mind is made up.pistons are being made as we speak,going with the 427,short block should be here in 6 wks
thanks for are the info.
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