Big block lighter than a small block?

rsimoes · #1 (**permalink**) 03-13-2005, 02:12 PM

I was looking at the www.fordracingparts.com web site and it says in there that the 514 weighs 543 lbs and the 392 weighs 669 lbs.

Is it possible tha the 460 is actually lighter than the 351W? (both have aluminum heads)

(I'm assuming that what there engines started out life as)

CowtownCobra · #2 (**permalink**) 03-13-2005, 02:20 PM

An aluminum block BB motor will in some cases weigh less than an iron block SB.

ENTDOC · #3 (**permalink**) 03-13-2005, 02:24 PM

must be a typo. 514-670lbs
392-545lbs chuck

rsimoes · #4 (**permalink**) 03-13-2005, 05:54 PM

The 670 pounds is the shipping weight, which includes all the wood packaging. . .

ENTDOC · #5 (**permalink**) 03-13-2005, 07:29 PM

correct,but the relationship to the 392 is the same. The small block is about 125lbs lighter. chuck

rsimoes · #6 (**permalink**) 03-14-2005, 10:52 AM

Are we talkin about just the block or a complete engine?

I have heard that it is 125 pounds lighter, 150 lbs lighter, 250 and 300 lbs lighter. . I'm not sure we're comparing apples to apples. . .

I wanted to know the total weight of the complete engine, iron block with aluminum heads weight difference. . .

Ford Racing could not answer the question and neither could Roush Racing, in fact neither one was friendly on the phone.

(comparing the Roush 427R (351W block) vs the Ford Crate 514 (429/460 block)

ENTDOC · #7 (**permalink**) 03-14-2005, 11:43 AM

at least according to my ford racing parts book,the complete motor as shipped is what we are talking about. I cannot tell you how much the packaging material accounts of the totals however,but Iassume the packaging would weigh about the same for both.chuck

cobrashoch · #8 (**permalink**) 03-17-2005, 04:31 PM

Engine weights vary dependant on how they are built and what castings are used . For example a factory iron 460 block weighs from 175 to 220 lbs dependant on casting and year, and 351 blocks range from about 135 to 165 for a early truck block. The weight of crankshafts vary too, but the % of weight lost favors the aftermarket big blocks crank with the Chevy rod setup, as apposed to it's stock weight. Most (not all) small block stroaker cranks weigh the same as stock or even a bit more, and that includes most of the small journal stuff out there.
The upside and the downside to this is All Ford V8's can be built normal or lighter if attention is directed to factory castings, etc, if you were to work at weight as a objective.
As for most of these Cobra motors, (using factory blocks and aftermarket stuff) I tell people that most times the engines go up about 50lbs for each step/up in each block casting class.
So 302 combos come in at about 350 lbs, plus or minus. 351 combos at roughly 400, FE's at roughly 450 total and 385's a tiny bit over 500 most times. Bet that's why nobody wants to quote you engine weights? You see, they know better.
My 385, a 30 over 460 with a 4.5 inch stroaker crank, w/Chev journals and Blue Thunder heads came in at 545lbs with a few accessorys on for example.
My own opinion is the difference in weight between even a 302 and a built 460 is really small in a ill handling Cobra. Other than in drag racing I would NOT be racing ANY Cobra with a iron block!
Cobrashock