Engine Mods

I have searched the forum for this info so don't flame me please. I have a 93 Sport Nautique with the GT40 motor. I want to upgrade the rockers to full roller 1.7 to 1 rockers and put on a better intake manifold. I have three questions.

1) What rockers will fit under the PCM valve covers and are reasonably priced?

2) It appears I have from 3 to 4 inches (rough guess) clearance under the engine cover. Is anyone familiar enough to tell me whether I can fit a Performer RPM manifold under it? Suggestions for other manifolds would be appreciated.

3) Also I have a DUI distributor coming because the stock distributor only had 12 degrees of advance (and the hole shot would still pull your arms off) - will the DUI interfere with the after market manifold?

Thank you ahead of time.

TiminMem wrote: 1) What rockers will fit under the PCM valve covers and are reasonably priced?

IMO reasonably priced is not a good idea on valve train components. Something like Harland Sharp or Ford Motorsport would be good.I don't trust the cheaper ones,why are they so much cheaper?
Tim's idea of just changing the cam would,in your case be a better idea.

The 1.23 holds a pretty significant holeshot advantage over the 1:1, top end is about the same. Since you have a 1:1, you have a RH (reverse rotation) engine, which limits your cam choices. There seem to be limitations on the crop of blanks currently available, which makes going to 1.7 rockers a serious consideration in place of a cam upgrade.

I would not go with cheap rockers. I didnt copy and paste your link, but assume that if you had to ask, then the answer is yes. Joe had good things to say about Scorpion, which is one of the lower cost brands, but I have only dealt with Crane (gold) rockers, and FMS (which are rebadged Crane golds). Those arent particularly cheap to buy brand new.

I was able to fit a Stealth under my '90 motorbox by going to a shorter (2" is the shortest you can fit over the j-tubes) arrestor. Your Sport is probably the same- it is very tight. Arrestors can be hard to find though- so if you end up eliminating the spacer, you can plumb the PCV into the baseplate of a newer Holley, or into one of the runners on the intake manifold (though I dont particularly care for the latter option).

And the firing order is 1-8-4-5-6-2-7-3 and model number is PRP-PT-R10 (All those R's are giving me a sinking feeling) if that helps. Oh well my distributor just went up 75 dollars!

Just edited my post - thanks I will call performance distributor and get pinged for the 75 more dollars! I'll look up the golds! Thanks btw your screen name comes up everywhere.

Crystal! Thanks for the help.

Performance distributors knows ignition stuff pretty well, but I wouldn't expect them to be marine experts. Theyre the distributor manufacturer and not a huge retailer. Rotation convention automotive vs marine is backwards, so it's not surprising they goofed. I would always check CCF first with this sort of thing.

The RH roller blanks never existed, but can be custom made by a few different specialty cam houses (LSM Engineering in MI is one of them). The downside, of course, is that theyre not cheap. We had one made for our BFN and it was definitely worth it though.

$750 from LSM is what Ive been quoted. Dont forget to factor in $400-500 for tie bar roller lifters, and maybe $200 for new springs. About a $1500 upgrade, all said and done.

Final question Tim - the springs don't stack up with the 1.7s do they? Please say they are fine!