Hot Rod Forum banner

351w main caps

10K views 16 replies 9 participants last post by  Max Keith 
#1 ·
My sisters boyfriend asked if i would help him build his new engine for his mustang. He got a 351w from a 69 cougar for free(just the block and heads), but it didnt come with the main caps. he said he called a bunch of different machine shops and they just told him they cant put new ones on. to me that didnt sound right. I just wanted to know why they would tel him this. if its true he cant do it we'll just build a 302. any help is greatly appreciated.
 
#2 ·
It's true. A block with no main caps is JUNK!. Unless you want to spend many many dollars finding caps that fit correctly and having them line bored/honed to fit the block.

As a block is machined in the factory the caps are bolted to it, The main bores can be off in any direction. Depending on how much wear is present on the manufacturers line. Chips under the block. Operator skill etc.

Better go with the 302..
 
#5 ·
It may be $125.00 for the line hone. But, unless you can do the work yourself. You will also have to pay labor to rough fit the caps, if they can be fitted. Center cap (thrust) has to be fitted side to side, up and down and forward and back. The last Ford I did with mismatched caps cost the owner more than $300.00 in labor costs. Plus he had to get three different sets of caps before something close to even fit was found. Loose timing chain also.
 
#7 ·
Yes, Actually the aftermarket caps are harder to install. They almost always have too much height, have to be cut down on a mill. Then you have to cut the side index to center the cap.. Align bore/hone, Recut the bearing tang. The Thrust is most important. On a Chevy that usually remains stock. But still a lot of labor, assembly, checking, adjusting and reassembling. Before the actual operation. Who pays for the extra?? Not one shop around here will do mismatched caps or aftermkt caps on a block in and out the door. Cleaned, bearings, etc.for less than about $500.

It just grates on me to see people say that a certain operation only costs xxx amount of dollars when they don't consider the actual costs. Or have only HEARD that price from someone else.

I used to get kids in the shop that would want a block bored and honed for the advertised price on the shop list. Not taking into account that the block has to be stripped, bearings&plugs removed (1) Cleaned (2) Checked for cracks (3) Bored, honed (4) Recleaned (no chg) Cam bearings install (5) soft plugs install (6).

In my book that ads up to at least 6 labor/machine operations which must be charged for. Unless you like to work for free. I'm sure the customer doesn't work for free. BOB :D
 
#9 ·
The Main thing

You would be about as well off and money ahead to just go out and find another short block to work with. I dont know about in your area, but around here, a rebuildable (read as needing a serious overhaul) can be had for scrap iron prices, regardless of the make or type. (Standard production engines that is).
You should be able to easily find a GOOD rebuildable 351W for under $100.
Use the 69 heads on it and go from there.
 
#11 ·
There's an old saying among old mechanics, "we can make anything work, as long as you got the money" If you have a 302 block, go with 302 heads. You can always port the heads and install larger valves for better flow. Is this for a street rod, or a track racer? If it's just for a street rod, then making mild Mods can give really nice performance, good streetable driving, and a reasonable cost. BUT, if it's a 1/4 mile car, then go with a set of Rat heads and matched cam for whatever block you have. Those babies will twist the windows out of a car.
 
#12 ·
351W head on a 302

They definately will fit, and would breath better than most any 302 head.
The one thing I recommend if you dont do anything else is to grind out the tonsil in the exhaust port. That critter is very restrictive and can free up quite a bit of exhaust flow.
The 351 heads have 1.85/1.56 valves vs. the 1.78/1.48 valves in the 302 head. It is recommended that you use the shouldered head bolts for the swap.
Ive used 351 heads on a 302 and use the stock bolts and never had a problem but you never know.
The 69-70 351w heads have a 60 cc combustion chamber. The only heads the 302 have that have a smaller chamber are from 74-75 era with a 58 cc head, but are extremely restrictive. Before and after that they range from 64-69 CC, on the 302. Your 351W heads are about as good as it gets for a factory head, other than the GT-40's.
Since your rocker arm studs are pressed in type, you will want to cross pin them into the bosses, so they dont pull out with stronger springs and higher lift cams.
The way you do that is to use an 1/8th inch drill, drilling from the intake side, drill through the stud boss and stud, then drive an 1/8th inch by 1 inch roll pin into the hole. This will keep the studs from pulling out.
Being a Ford man, got a lot of other tips on working on Winsor heads as well.
 
#14 ·
BOBCRMAN@aol.com said:
Yes, Actually the aftermarket caps are harder to install. They almost always have too much height, have to be cut down on a mill. Then you have to cut the side index to center the cap.. Align bore/hone, Recut the bearing tang. The Thrust is most important. On a Chevy that usually remains stock. But still a lot of labor, assembly, checking, adjusting and reassembling. Before the actual operation. Who pays for the extra?? Not one shop around here will do mismatched caps or aftermkt caps on a block in and out the door. Cleaned, bearings, etc.for less than about $500.

It just grates on me to see people say that a certain operation only costs xxx amount of dollars when they don't consider the actual costs. Or have only HEARD that price from someone else.

I used to get kids in the shop that would want a block bored and honed for the advertised price on the shop list. Not taking into account that the block has to be stripped, bearings&plugs removed (1) Cleaned (2) Checked for cracks (3) Bored, honed (4) Recleaned (no chg) Cam bearings install (5) soft plugs install (6).

In my book that ads up to at least 6 labor/machine operations which must be charged for. Unless you like to work for free. I'm sure the customer doesn't work for free. BOB :D
So now you assume everybody takes the block in needing all this work?

At my shop, they charged me a grand total of $500 for a cleaning, wet mag, deck to 8.98, bore\honeto .040, align hone to square, honing of lifter bores, to cam tunnel, cam bearings and plugs with oil holes enlarged, and a sand blasting.

Prices might be different at your location but here, it's $125 to fit caps.
 
#15 ·
351W redux

I tend to agree with Red65mustang about yards not wanting to deal with short blocks, but there are a few that will do it.
The one thing about it is this, if you are wanting to get aquanted with doing porting work, the two heads you get with your long block, providing they arent one of the more desireable sets of heads, you can use them for practicing with your grinders.
Price again for a long block can vary, depending on geographical location and how well you get along with the guy running the yard.
 
#16 ·
Max Keith said:
You would be about as well off and money ahead to just go out and find another short block to work with. I dont know about in your area, but around here, a rebuildable (read as needing a serious overhaul) can be had for scrap iron prices, regardless of the make or type. (Standard production engines that is).
You should be able to easily find a GOOD rebuildable 351W for under $100.
Use the 69 heads on it and go from there.
Wow, where do you live to find bargains like that? seriously.
 
#17 ·
where do I live?

I live in the SE corner of Iowa, and over the years, when I was racing, developed a raport with a couple salvage yards, as well as friends that salvaged a lot of cars.
As I said, getting a rebuildable engine, meaning one that needs a total going over, can cost as little as $100, which is what I have paid for a couple of them. The most I ever paid for a long block was $250, and it was a running engine.
The best thing to do is to go out there and make some good contacts. You would also do well to look in the classified ads, trader papers, etc. Its not uncommon you can buy an entire running car for what you would have to pay for the engine, alone, at some salvage yards. The nice thing about doing it that way, is there is always the possibility you will have other parts you can use. And, if not, you can always sell the left over car for salvage, and pick up $30-50 bucks off of it.
When youve had to do it the hard way, with little extra cash, it pays to check out every venue, not to mention gaining valuable experience in horsetrading, and mechanical knowledge. I actually got one vehicle given to me for cleaning out a barn once. I dropped another transmission in the car, which I had laying in my pile, and sold the car for $500.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top