Andy Tuttle

Have a '68 Coupe that is getting a 427 tall deck. Does not have any exhaust at this point. Is TD exhaust the same as SD? In other words can I run standard headers on my engine? TIA Andy

gbvette62

If the 427 tall deck block, is anything like the tall deck blocks used for 572's, you'll either need to custom fabricate headers, or modify an existing set of headers.

crf311

I'm running a set of Brodix alum heads on my 454 that have .5" raised exhaust ports. The headers I used are the hedman std . 454 headers. I did have to massage the #3 and #4 tubes for steering box and frame clearance.

TheSkunkWorks

The tall block is has a nominal deck height of 10.200" verses the standard's 9.800". ...which in the case of a short stroke such as the 427's begs the question, why? If it's about rod length, given you're most likely looking at custom slugs anyway you could just adjust the pin height for .250" or .400" long rods in a standard block (~1.7:1 or ~1.74:1 rod/stroke, respectively), avoiding unnecessary reciprocating inertia and weight. Just my $.02.

mikem350

Sounds like the OP wants to use the tall deck truck motor as is?? So what you are saying is the exhaust outlets on the head will move the headers up 0.4 inch, and out some due to the new angle.

If that's the case there are spacers available that permit use of regular BB intakes too. There is info in the archives about truck BBs.

Andy Tuttle

I believe the 572 td uses the same block as the 427 td. Would the modification have to at the head (do sd and td manifold/header mount the same, same bolt pattern and distance etc) or in the tube body ("dented" or adjusted for clearance or lengthened to drop low enough). Thanks

Andy Tuttle

Do you have a picture of that and how much you had to "massage"? Had any issues from heat on the steering box?

Andy Tuttle

Yes, I am looking at using the td motor as is. An engine builder in Des Moines, Iowa changed it from a 4 ring piston to a 3 ring, changed the cam and other parts before I got it. It was running in a pickup truck, highway speeds and performing very well for the previous owner wrecked the truck when he was driving drunk. I was aware of the ability to change the intake by using spacers, and will be getting them as well, if I proceed with this engine. So yes what I am saying is are the exhaust outlets on the head different than an standard bb. And I had never realized the block was not only taller, but also wider until I read the post from SkunkWorks and you, so thanks to both of you! I have an L88 hood, so I think I will be OK on height but not sure about the rest.

mikem350

I installed Heddman headers on my 66 BB and had to dent the tubes at the box and I think the idler arm. No big deal, everybody with a bb does the same. In your case might have slightly more interference due to the extra width. Yes they will heat up the box...it does happen, but so do iron manifolds.

I bought the headers, fitted and dimpled as needed, and then had 'em Jet coated, which cuts down the heat. One or two plugs also were tricky, think I dimpled at the bend to get a wrench on them too.

I would be careful about intake selection, even with the L88 hood.

Andy Tuttle

Do you have an idea of how much wider a td is than a sd? and any recommendations on the intake? I am all ears! Also, are M/T valve covers out of the question also for clearance sake?

Andy Tuttle

Can somebody tell me the width measurement of a standard deck 427 or 454? TIA

mikem350

The 572 crate motor is a TD and dimensions are similar. Search the archives for this swap. You can also check the C2 forum, same chassis, but fiberglass is different.

Are you using the peanut heads?

Andy Tuttle

What are peanut heads? I have oval port but that is all I know. Will check on 572 swap. Thanks!

TheSkunkWorks

FWIW, tho I have a few BBC blocks on hand, including a couple of tall decks, by the maths below (and which I tend to trust more than my ability to accurately measure with a tape) the tall deck is ~0.566" wider between cylinder banks at the top of the bore CLs. HTH


cos(45*) x 0.400" x 2