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Help: What Can I Do to improve the CID and The HP of a 361 ?

1687 Views 9 Replies 5 Participants Last post by  BB361
Dear all,

I need Your help abouth the following:

I have a Block 361 (I di not have the heads) and I a read that I could change the stoke and the Bore to have more HP and a 502 CID, in such sense
1.-Where Can I buy the necessary parts to get it?
2.-What are the heads to this block and Where to buy them?

Please the webs to buy the parts?

With My best regards.
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This will require a stroker kit and be very expensive, and I believe there is a problem with finding the proper pistons, but, if you take a set of 400 Chevy pistons (4.125 bore, same as 361), and with the proper altered piston pin (bushing the rods for the 361/383, then recalculate the new stroke, I believe there would be an application of a very expensive crankshaft custom made for this application. There is one other way to make a 400 cubic inch engine, and that is to use a 413 or 440 crankshaft cut down to your journal size, then have the proper height pistons added from the 400 Chevy collection, or any custom 4.125 piston after you calculate the piston height needed.

There is no way to get 502 out of any calculation, the largest crankshaft you can put in a 361/383 is 4.15 inch stroke, which requires a lot of external oil plumbing, internal shaving of casting, and you come up with 443 cubic inches. In my opinion, for the cost of doing this, and the trouble to go through to make the necessary alterations, put a blower or turbocharger on it and have one heck of a strong 361 B block engine. The difficult part is cost of the parts to make it work.
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Best way to do this is to get another engine.
361's are very competitive as they are. A good cam and heads will give good results. My '65 in a Bellvedere II body ran 13.98 -14.10 at 95-99 MPH with just 4.11 gears, hydraulic cam and stock heads with an angle valve job. Factory 4BBL intake and a Holley.
I tend to agree, It is a 383 with an 8th inch smaller bore, which lets it rev a little faster.
A friend of mine built a monster of a 496 from a 440, and he still has cooling issues from time to time. Bigger than that probably requires a new block with siamese-cast cylinders, and I would think that problem would be magnified with the 361...
Dear all Thanks for Your replies.

I think that is too expensie and complicated to do it so I will buy the heads, Do You know where?. and with a 4 barrel, New psitons (My doubt is Could I Use the piston for a 383?) I could have a good 361. The cam shaft? any recommendation please?

My next idea is fo find an original 383, What can I do to improved?

With My best regards
You can use any B or RB heads, 361 original early pre-1964 had closed chambers which raises your compression, and there are several aftermarket aluminum heads, just do a search to find them. The engine likes a cam with a 275 degree duration and .475 lift. An aftermarket of stock 361 or 383 dual plane intake works well.
Just so that you keep it in mind, there are two variants on the big-block family.

The 350, 361, 383, and 400 are "B" engines, and generally things like intake manifolds and valley pans will interchange.

The 413, 426, and 440, with one or two years of a different oddball 383, are "RB" engines, or "Raised B". Their intakes and valley pans will not fit a "B" engine.

Heads should fit all years.

I suggest that you purchase a book on building big-block mopar engines. "HPBooks" has offered such books in the past and they can be quite useful, often casting numbers and other such parts are specifically identified.
Thank for all Your support

Best regards
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